Hi gang; I'm a long-time lurker on the forum and have been learning oodles over the past 2 years. I began construction of my cnc about a year ago, but only recently found the space (in my Dad's garage!) to attempt completing the build.

I will be making a modified Solsylva belt-driven cnc within a completely enclosed box to control dust propagation. The CNC frame itself will be welded steel and have a table area of 48" x 30". Since I have to operate in a section of the third car garage, I am trying to make everything as compact as feasable.

I have already built the hobbycnc controller and will be using the 305oz-in steppers. The majority of the gantry parts have also already been cut out and drilled on a POS Harbor Freight drill press. I used a caliper, center punch, and Dykem to locate the holes, but I think slop in those crappy bearings are going to be the limiting factor in regards to the accuracy of the placement. Hoping to get .001" - .003" accuracy over the length of the table when the machine is complete.

I'll start of with a few pics:

1) Here a draft of the overall design concept. The box sides will be hinged to allow accomodation of oversized pieces.

2) My Dad in the process of helping me put together the "box". Completion of the box will be the next step in the build.

3) All the gantry parts drilled and ready to go. Will begin assembly after the housing box is completed.

4) The results of my Dykem layout and crappy Harbor Freight drill-press.

Did you use a center punch and center drill on those holes?

Did you use a center punch and center drill on those holes?

Yep. Center punch, and a 1/16" pilot hole and then stepped drill sizes to the final size.

I finished up most of the box today by adding gussets to stabalize the whole thing. It is VERY stiff! I can sit my 180Lbs butt on the table and jump up and down with no perceptable flex. The table top (mdf) sits flat, but the table frame is not completely flat. Rather than screwing the mdf on, I will need to use some gap filling glue (silicone?) to ensure that the table top sits nicely. Just for the record, I HATE this polyurethane "gorilla glue"; the stuff foams and gets everywhere! Hope a bit of paint will make it all look better ...

Pics:

1) A detail of the framing.
2) The mdf layed on.
3,4) An example of the gap
5) Table flat

Lest anyone think I've been slacking, I've actually been hard at work on this machine; made some progess, had some setbacks, and learned LOTS of lessons ...

1) GAS PIPE sucks for rails! This stuff is just not straight. I sanded mine smooth, and my neighbor even asked if it was stainless steel because it looks so purdy :) . Even though it looks straight to the naked eye, there are minute twists and variations in the surface. I was hoping to get .001" accuracy per foot over the length of the table but I now feel even .01" per foot might be pushing it. If I had a lathe, I would turn it down, but lacking the resources and funds I will live with what I've got.

2) When modeling with CAD, make sure you model nuts and account for their clearances. I have had a ***** of a time grinding parts down to make them fit. A dremel has definately been my best friend on this proj so far.

I'm gonna try to bring this thread up to date with what I've completed thus far.

Pics up next ...

First up - the gantry beam. This consists of an aluminum channel with gas pipe rails which are drilled and tapped and bolted on atop a 1"x1/2"x1/8" c-channel. I started off using "shelf standards" for the rail supports. This stuff is basically stamped sheet metal and as crooked as a politician's smile. I switched it out for the 1x1/2" aluminum extrusion which was very straight. The differences in clearance required me to futz with the rest of the machine so everything would fit correctly. A painstaking take-apart, grind, fit, take-apart, drill, fit, grind process ensued that took a few days to complete.

PICS:

1) A rendering of the parts which have been completed so far.

2) The gantry beam laid flat.

3) The gantry beam end view.

Next up, the gantry side plates. These go on either end of the gantry beam and have bearings that ride on the x-rails (which have yet to be constructed). The idlers are made with pvc piping per David's instructions. The construction of these plates went off without a hitch.

PICS:

1,2) Side plate (stepper side). This will eventually carry the y-stepper motor which will drive the z-car via a belt. Note the "figure 8 cutout" - it was meant to be circular to house a bearing but i made a small boo-boo :). It shouldn't effect the performance though. Note that the x-pulleys have not been attached yet.

3,4,5) Side plate (belt-tensioning side).

Now is when things started getting REALLY hairy. Construction of the gantry z-rails. Again, I started off using shelving standards, only to discover that it was not straight. I replaced it with 1x1/2x1/8" c-channel extrusion and that created some real problems with placement. Everything in the z-car is VERY tightly placed, and this change seemed to ripple out, redimensioning all the nuts, holes, and clearances in the carriage.

I rebuilt the entire z-rail system only to discover it was still twisted a small amount (1/64" or so). Come to discover it was my gas pipe rails that were buggering me up all along... Oh well - 1/1000" is pretty much out the window now :violin:

PICS:

1,2,3) Z-rail. The spindle will eventually mount to the bottom plate.

4) The belt retaining/tensioning mechanism. Although this looks big, the whole thing is pretty small. Those screws are 1/2" #8 machine screws.

Next up the z-carriage. The entire assembly will ride along the gantry beam providing z and y axis movement. As mentioned above, the clearances here are excruciatingly tight. I had to grind off almost every nut to make everything fit correctly.

PICS:


1) Z-car front. Z-bearings are mounted here and pulled in to the z-rails via 1/4" threaded tensioning rods (not shown here)

2) Z-car back. Houses the y-bearings which are pulled to the rails via tensioning rods. If you look at the bottom angle, you will note that it had to be mangled to allow for the shorter clearance of the new aluminum extrusion rail supports.

3,4) You can see how close the bearings rotate to the nuts. They had to be ground down to prevent rubbing on the bearings and causing binding.

And now the whole z-car assembled (minus the drive mechanism). This took a week of tweaking to get all the clearances working without binding. VERY frustrating, but (hopefully) working now :tired:.

PICS:

1,2) The z-car with z-rails and tension members in place.

3) Top tensioning member. Note how close they are to the z-rails. The z-bearing bolts and nuts had to be ground down to allow the bearings to sit slightly lower and create clearance.

4) Bottom tensioning member. Tight again!

The z limits of travel will be defined by where the belt clamps begins to impinge on the pulleys. I will need to put some sort of mechanical stop here as well as limit switches.

PICS:

1) Bottom travel limit.

2) Top travel limit.

More updates to come soon!

Wow, sonic, you've been busy! That is certainly going to be one stout carriage! I can't believe you got all that stuff in there - the fit was tight enough in the basic design!

I do have a couple of comments, looking at the pictures - I would get some nylock nuts and use them everywhere. After my table started running, any bolt that had jam nuts would eventually loosen. This was even after I used Locktite (the blue removable one.)

It looks like you've got aluminum pulleys. So do I, but I've had to order some steel ones that go on the steppers - they would work loose, especially on the Z axis, which has to lift the carriage and the router. The steppers have a flat on them, and the set screws were in line with them, but they still worked loose. As soon as they slip you've lost steps, which ruins the work. Trying to tighten them, when there is only 1.5 to 2 threads to hold on to, just doesn't cut it. And yes, this after using the Locktite stuff. I hate set screws. I am going to try the steel pulleys, and if that doesn't do it, I am going to look at pinning the pulley to the stepper shaft.

Although the black pipe might seem rough, since the gantry is rested at four points it evidently gets evened out a bit as it travels. I know the pipe was much straighter than when I started tightening the mounting nuts. Getting them firmly attached without distorting the pipe took me quite a while. Much is made up for by making a constant Z pass with an endmill across your sacrifice board - whatever variation there is in Z as X and Y changes is somewhat compensated by this. I thought about getting some better rod, but that costs lots of dinero, but we can always upgrade to that if need be later.

Anywho, looks like you're doing a great job on your table, and I hope it works like a swiss watch for you! :cheers:

I would get some nylock nuts and use them everywhere. After my table started running, any bolt that had jam nuts would eventually loosen. This was even after I used Locktite (the blue removable one.)

Nylon nuts would seem to be a good idea, but many of the nuts have been ground down. I would hate to have to go through this again. If they loosen, they're going to get hit with red locktite. That stuff is like epoxy - it ain't going anywhere!

It looks like you've got aluminum pulleys. So do I, but I've had to order some steel ones that go on the steppers - they would work loose, especially on the Z axis, which has to lift the carriage and the router. The steppers have a flat on them, and the set screws were in line with them, but they still worked loose. As soon as they slip you've lost steps, which ruins the work. Trying to tighten them, when there is only 1.5 to 2 threads to hold on to, just doesn't cut it. And yes, this after using the Locktite stuff. I hate set screws. I am going to try the steel pulleys, and if that doesn't do it, I am going to look at pinning the pulley to the stepper shaft.

Yeah, I noticed slippage on some of the pulleys as well. I'm probably going to end up drilling my shafts to pin the pulleys.

Although the black pipe might seem rough, since the gantry is rested at four points it evidently gets evened out a bit as it travels. I know the pipe was much straighter than when I started tightening the mounting nuts. Getting them firmly attached without distorting the pipe took me quite a while. Much is made up for by making a constant Z pass with an endmill across your sacrifice board - whatever variation there is in Z as X and Y changes is somewhat compensated by this. I thought about getting some better rod, but that costs lots of dinero, but we can always upgrade to that if need be later.

Thanks for the comments, I only hope my machine ends up half as nice as yours.

The problem with my gas pipe is that it has a slight amount opf curvature to it. Even though the diameter has been sanded down to within .001", it ain't straight. One of my frustrations is that I don't really have a precision straight edge or square, so I am relying on calipers. I finally got so frustrated trying to measure everything, that I just pinned everything down. I've kinda resigned myself to the fact I'm not gonna get .001"/foot. This may not be the best plan, but I'll worry about alignment when i get movement :rainfro:.

Okay - two steps forward, three steps back :(.

Yesterday I tried to drill large holes (3/8") in my gas pipe rails and it was a TOTAL disaster. I ruined a polished pipe that took me a good 2 hours of work to get to that stage.

I also took my y-axis for a "test drive" by mounting a mechanical pencil on the gantry and manually moving it to draw a line. I am MUCHO disappointed with the results. The gas pipe is bowed and this shows in the resulting line. When a straight edge is placed against the line, the deviation is at least 1/32". This is completely unacceptable to me.

I am at the point where I am re-evaluating using gas pipe at all and thinking of using either drill rod. stainless steel tubing, or 1018 cold rolled steel rounds for the rails. Keep in mind I am an unemployed student, but I would rather spend a little more now than regret my performance later on. Which of these (or any other) options do you think are my best?

I think your problem is more likely the way you're mounting the pipe than the pipe itself. There have probably been over a hundred of Joe's 2006 machines built with gas pipe, without the straightness issue you're having.

I think your problem is more likely the way you're mounting the pipe than the pipe itself. There have probably been over a hundred of Joe's 2006 machines built with gas pipe, without the straightness issue you're having.

Yeah, I have never heard of anyone complain about gas pipe before. But, the pipe itself it definately bowed. If I unmount it and hold it against a "reference" edge (cold rolled steel plate), one can see light enetering at both ends indicating that there is a bow in the pipe itself. I believe that the diameter is fairly even, but the linear accuracy of the pipe is in question.

I have the pipe mounted against a c-channel 1x1/2x1/8" aluminum extrusion and 6063 aluminum c-beam that have been measured to within .001" over their length. This is why I am thinking that the gas pipe is the culprit.

I'm thinking the aluminum channel it's in could easily spread open and let the pipe sit deeper in spots.

Ger21: At your suggestion I removed the rails from the beam today. In regards to spreading the channel legs apart due to tightening, I was very careful not to overtorque the nuts and also went with thicker (1/8" vs 1/16") channel to help avoid some of the problems with speading the extrusion legs.

However, you may be right that the bend in the rails is due to the way I have them mounted. Specifically, although the holes I have drilled in the pipe are linear, my taps are not perfectly perpendicular; they are not perfectly lined up. This may be causing the bend I am seeing.

The pipe itself is bowed a slight bit, but it is rather like a wet noodle; placing a torque on the rail bends it fairly easily so this may be a non-issue. I'm going to have another go at re-drilling, and re-tapping the pipe with a bit more precision this time.

I'll let y'all know the outcome ...

Remounted the pipe today -

And - it is much straighter this time :). What was happening were that the rails weren't parallel to each other and this created a curve as the gantry rode on the rails.

I still suck at drilling pipe, however. No matter what I do, I cannot get these darn holes co-linear. My current process is as follows:

1) dying the pipe with dykem
2) Using an aluminum c-channel to score a straight line on the pipe.
3) Measuring and marking where the holes should be.
4) Center-punching the holes
5) Pre-drilling with a 3/32" bit.
6) Stepping up in size to the final hole size.

I am still finding that the final holes are not turning out co-linear! To compensate, I am enlarging the holes on the gantry beam and taking a bit more time to align everything before tightening the rails to the beam. Anyone have a better way??

Do you have a drill press, or are you hand drilling?

I have a drill press - but it is a cheap chinese goodie. Hand drilling might actually be more accurate :) !

Clamp a fence to the table, and drill the pipe while it's in the channel. maybe tape it down so it can't turn, and they should all line up perfectly.

Spent the entire day drilling frigin' gas pipe. I finally got ONE 30" x-rail drilled to 5/16" accurately (thanks ger21). This has been the most tedius part of the build thus far. I took pictures, but on the computer screen, the non-colinear holes look the same as the co-linear ones! I'm not looking forward to another day of drilling ...

I've got an engineering question for y'all. The plans I have call for three 3/8" bolts supporting the rail. Can I get away with eight 5/16" bolts supporting them instead? I am unsure of the forces that are transmitted to the rail while cutting ... anyone have a clue??

PICS:
1) Co-linear holes
2) 5/16" bolt in hole. Disregard the clutter in the background; the rails will be mounted to the tubular steel frame with these bolts as "standoffs" every four inches.

If you think its the bit wandering as you drill (small diameter bits are very susceptible to this), try a center drill, sometimes called a "countersink" - it's what lathe machinsts use to prevent wandering.
Picture of one:
http://grizzly.com/images/pics/jpeg288/h/h4463.jpg

A center drill will not wander. (well, not too much anyway.)
Also, if you think the pipe is wandering, HF has a cheap v shaped holder for pipe to rest on using a drill press. Once the first hole is drilled, attach a stud to it to help indicate that the pipe is rotated upright, and that it stays that way while you drill.

http://www.harborfreight.com/cpi/photos/92000-92099/92046.gif

Then, if you touch a center drill to the punch mark before drilling, the pipe should be lined up and it should drill true. Once the pilot hole is through, drilling to the final size should remain pretty concentric as long as your final size drill has equally sharpened cutting edges (read: use a new drill if possible). You can get center drills and the above v rest for less than $10 at HF.

All the above is to get the holes to align. As for the forces, there really isn't too much rotation or twist forces on the pipe, mostly just sideways forces as the momentum of the gantry changes, it wants to rock the pipe in the Y axis direction, and you don't want that to move. Since its on ball bearings, though, most of the force is on the gantry side plates and the leadnut. Steele in his plans says it ok to overdrill if necessary to align the studs - all that matters is that they are tight and stay that way. Make sure you use washers that deform a bit when they are tightened - I think they actually help keep the studs from coming loose!

revarguy: thanks for the detailed and thoughtful response. Amazingly, I tried using the Harbor Freight pipe jig without much success! I finally happed upon a procedure that worked for me, albeit tedious and time-consuming: I scribed a line on the pipe, center punched the hole locations, mounted the pipe to a channel with duck tape, and drilled up the holes by 1/32" each pass until I reached 5/16"! Even with this, there was a tremendous amount of bit deflection, probably on count of my cheapie HF titanium drill set. But, they have done the job for me by using lots of lube during the drilling process. The holes are probably off by a couple of hundreths of an inch, but I've oversized the rail support holes to compensate.

I'm just glad this part is over! Next up will be welding the frame together and then my Franken-cnc should start taking shape :)

With all the drilling done, I had a fun and productive day today. I tack welded part of the frame structure together and everything looks very square so far (knock on wood). I am using slightly thicker walled tubing (.120) with my stick welder because I have had bad experiences with warping when welding thinner tubing. Hopefully my tacks won't pop when I lay a full bead; I am staggering my welds to minimize draw but I am by no means a "welder".

PICS:
1) Frame plan
2) Raw materials
3) Tacked together and square!
4) Top view, everything lines up ...
5) Rails on top - the final assembly will not have the aluminum extrusion, it will be mounted with through bolts so I can fine tune placement.

If you think its the bit wandering as you drill (small diameter bits are very susceptible to this), try a center drill, sometimes called a "countersink" - it's what lathe machinsts use to prevent wandering.
Picture of one:
http://grizzly.com/images/pics/jpeg288/h/h4463.jpg

A center drill will not wander. (well, not too much anyway.)
Also, if you think the pipe is wandering, HF has a cheap v shaped holder for pipe to rest on using a drill press. Once the first hole is drilled, attach a stud to it to help indicate that the pipe is rotated upright, and that it stays that way while you drill.

http://www.harborfreight.com/cpi/photos/92000-92099/92046.gif

Then, if you touch a center drill to the punch mark before drilling, the pipe should be lined up and it should drill true. Once the pilot hole is through, drilling to the final size should remain pretty concentric as long as your final size drill has equally sharpened cutting edges (read: use a new drill if possible). You can get center drills and the above v rest for less than $10 at HF.

All the above is to get the holes to align. As for the forces, there really isn't too much rotation or twist forces on the pipe, mostly just sideways forces as the momentum of the gantry changes, it wants to rock the pipe in the Y axis direction, and you don't want that to move. Since its on ball bearings, though, most of the force is on the gantry side plates and the leadnut. Steele in his plans says it ok to overdrill if necessary to align the studs - all that matters is that they are tight and stay that way. Make sure you use washers that deform a bit when they are tightened - I think they actually help keep the studs from coming loose!

Ya know Rev it on the head, ya definitely need to get some center drills then ya can skip this step drilling process and do it like the pros do it! Looks good so far , I might bring the back of your stand all the way to the floor and add a cross member along the floor to help prevent any side to side movement. So that the whole back of your stand is solid plywood backing(if thats what your planning on using).

Ya know Rev it on the head, ya definitely need to get some center drills then ya can skip this step drilling process and do it like the pros do it! Looks good so far , I might bring the back of your stand all the way to the floor and add a cross member along the floor to help prevent any side to side movement. So that the whole back of your stand is solid plywood backing(if thats what your planning on using).

Yeah, that Rev is one smart dude!

I never took a pic of the completed stand, but I have added a shelving unit underneath to hold the electronics and computer. The legs have also been doubled to 4x4" dimensions. The whole thing is VERY stiff and I don't envisage there being a problem; but if I do get flex, your suggestion would be the best way to deal with it.

PICS:
1) Overall of the cnc enclosure
2) Detail of side - shelf end
3) Shelving for computers and electronics in here
4) Detail of leg. 4"x4" gusseted and screwed to a 2"x6".

Hot day today in So-cal: 90 plus! Tack welded the other rail suport together using the first as a guide. All went as well as could be expected - everything matches up as good as my square and eye can see. The last hundreths of an inch will be taken care of during the fine-tuning phase. Hopefully the welds won't draw too badly when I lay my fillet welds in to lock the whole thing together.

PICS:
1) The rails sitting on my welding dolly/bench. The bench was my first stick welding project and I am bringing the lessons I learned from it (re: weld distortion) to the cnc project.
2) The rail supports are pretty close dimensionally.
3) Side view of the rail supports
4) Closeup of the rail surface of the supports
5) Another view of the rails

6) This is where we are going - welding the entire frame together. :drowning: I am at a loss as to how to do this without twist while keeping the rail supports parallel to each other. My floor is not flat at all ... could I possibly weld on a sacraficial piece of mdf shimmed flat?? I have access to a granite slab, but it is not large enough to place the entire frame on it. Does anyone who has welded a square frame together have any suggestions?? :drowning:

Figured out a welding sequence to follow for the rail supports and welded the outside seams today. The result was the rail supports remained square! I have heard that butt welds are easier to minimize distortion on than fillet welds, so I have just left the inside corners tacked for the time being. The assembly is PLENTY strong as is and I am debating as to weather I even need a fillet weld; The more welds I place on this thing, the more likely it will be to distort ...

PICS:
1) First tacked all the corners in diagonal sequence to ensure the assembly remained square and free of twist.
2) Then welded the seams in this order to minimize distortion. Before welding each pair of parallel seams ([A,B], [C,D], etc.) I tightly clamped a gusseting member across the adjoining legs to help prevent distortion. Probably unnecessary with all the tacks, but better safe than sorry.

Hopefully this will help someone in the future - perhaps me when I forget :o .

So right now there are two questions lingering:
1) Should I complete the fillet welds in the rail supports or are they unnecessary?
2) How do I weld the base together when my floor is not flat?

Back when I was building some mobile benches for my 9x20 and minimill I was using 2" square .065 tube. I started welding up the base and found that I had an incredible amount of warpage. I ended up chaining it up between two pickups and straightening it with a come-along. Lesson learned.

Some suggestions:

Use thicker tubing.

Tack welds first.

Keep your beads short and don't overheat.

Weld on opposite sides of the structure to equalize the stresses.

Let it cool down before welding the same spot again.

Check for warpage frequently.

Tie two strings from corner to corner in an X. They should just touch where they intersect. Use this for setup as well as fabrication. Check for alignment and squareness frequently. Periodically alternate which string is "on top". This will help indicate if the base components are parallel.

It's easier to "adjust" a tack than a bead :)

Looking really good so far, looking forward to seeing more pictures.

degreaser: thanks for the summary, this more or less sums up what I have been attempting to do. My floor is far from flat, however, and I am concerned about introducing twist into the frame due to this. I talked with my mechanical engineer uncle last week and he answered my questions regarding needing fillet welds in the frame. The answer is "no"; as long as the structure is strong enough to handle the static load (60Lb gantry & cutting forces), there will be nothing to gain by completely welding up the structure (it will not make it deflect any less under cutting loads).

Here you go oodanner :).

Had a productive day today after having realized that I had made a silly mistake: the holes in the rail support were only drilled 1/16" oversize and due to my rail bolts not being completely co-linear, this would not provide sufficient adjustment later to get the rails perfectly parallel. Actually, it MAY have, but it would have been a real pain to enlarge the holes after the entire frame was welded up ... The rails supports, however, had already been welded up so using a drill press was out of the question. To compund problems, my handheld drill had a maximum chuck size of 3/8" and I needed to bore a larger hole; a quick trip to Harbor Freight for a cheapie 1/2" hand-held drill remedied this. The enlarging of the holes was easier than expected and I may have gone a bit overboard by enlarging them to 1/2" for 5/16" bolts. But, better too much adjustment room than too little :).

I also realized that the mdf base was unsuported against the sides of the frame in my frame design. Although it might be overkill, I decided to add two 4" base supports against the bottom sides of each rail support; these were drilled and tapped for 5/16-18 bolts so that the mdf work surface can be bolted down to the frame structure so it won't shift after being surfaced. I also bought some Harbor Freight permanent threadlock to mount the standoff bolts to the rails - time will tell if it holds.

PICS:

1) Buggered up non-colinear pipe holes. This, was the best I could do after 4 attempts :mad: !
2,3) Enlarged rail support holes to accomodate buggered bolts and allow for adjustment.
4) New frame design to support mdf base at sides.
5) One of the 4 base supports.
6) The whole assembly. The rails will actually be mounted with washers and nuts but I was too lazy to put them on for the pic.

You're welcome. Yours is looking good. I'm always interested in cool steel frame build threads. I'm finally getting off my butt and building one myself. :)

Welded together the base today. Ended up using a scrap piece of granite slab to do the welding on, clamping all the tube to the granite slab. Did my best to make it dead-nuts square but it's off a slight bit (paralellogram - diagonals off by 1/16"). The important thing is that the surface is flat for the most part. Interestingly enough, there was a slight bit of flex in the granite slab when clamping the tube to it. I think this may have caused the structure to be slightly out of square. I ended up destroyed the slab surface (which I believe is just an epoxy topcoat) but it's just a scrap anywho. The rails should have enough adjustment capability to compenstate for my warped frame structure.

PICS:
1) Base laid out and ready to weld. Note the granite slab.
2) Tack welded everything in place.
3) Checked for flatness - good enough for government work :). The diagonals licked each other indicating the frame was flat.
4) Finish seam welds.
5) Full structure as is will be when complete (just placed here for illustration)
6) The base and rail support assemblies.

I am contemplating having the base assembly bolt to the rail supports instead of welding them together. The frame is already quite heavy (120Lbs or so) and this might help facilitate breakdown and transport later. Do you all think that would be a good idea?

PICS:
1) Proposed area for a 4" piece of 1.5"x1.5" .120 wall tubing to be used to join the base to the rail supports. I'm thinking of two 5/16" bolts ...
2) Perspective of where these connection pieces would be welded on the base.

I had a major setback yesterday. It's going to be time-consuming and costly to repair this error.

I opted to weld the frame together completely. The construction of the frame went as good as could be expected without flat reference surfaces - there was no warp or twist I could detect. Then I went to place my rails onto the frame and mount the gantry beam...

The frame is too small for the gantry by about 1/4". I must've made a dimensioning error somewhere in my cad drawings (chair) - I've been kicking myself trying to find the reason for this and so far have come up empty.

I guess I figured the extra rail adjustment would allow me to get everything fitting (the 5/16" rail support bolts go into 1/2" diameter holes). Well - because my rail bolts were drilled all wonky, the adjustment was shot to all hell. I'm not even able to get the rails completely parallel, leave alone having any extra adjustment room :mad: !!

At this point, any fix is going to be very time consuming. My options, as I see them, are:

1) Cut the gantry beam down 1/4" and re-drill everything. Not a great option because I don't have a bandsaw to do this accurately. I guess I could use my miter saw, but that does not make very square cuts either.

2) Use larger diameter rails. Upsize to 1" gas pipe instead of 3/4". This will require me to re-sand and re-drill the new rails. Given all the problems I had with lining up holes on the gas pipe, I am not looking forward to this. Givn the current wonkyness of the rail bolts, however, this is probably going to be a necessity anyhow.

3) Re-engineer the bearing support design. Although the Solsylva design is brilliant in most respects, there is little lateral adjustment for the outside bearing. The way that angled bearing is supported also seems like it wouldn't be very rigid, although I have yet to get the bearings to hug the rail to test this out.

The Solsylva belt design (which has been updated to the rack & pinion design) was specified to go on a wooden frame. I opted to weld mine to make the structure more rigid. In the end, the wooden structure would have been cheaper and easier to fix. Live and learn.

PICS:
1) Welding set up. Used two granite slabs to get as flat as I could.
2) Side rail supports squared.
3) Weld at the junction of the base and the rail support assemblies.
4) The frame in its final resting place.
5) How the bearing assembly is supposed to hug the rail.
6) Disaster. How it actually DOESN'T hug the rail.

I'm ready to throw this thing against the wall. I need a break.

I maybe way off ... but why not try get new bearings ( larger outside dia. that make up the gap ? looks to be on lower end. I would think not to much stress on that location ... just a thought :)

Kent

I maybe way off ... but why not try get new bearings ( larger outside dia. that make up the gap ? looks to be on lower end. I would think not to much stress on that location ... just a thought :)

Kent

Dear Kent,

Thanks for the suggestion; it would be wonderful if things were that easy! Unfortunately, enlarging the bearing would have it interfere with the timing belt that guides the x-axis. The clearances in the Solsylva design are very tight here. I would need to raise the idlers which would require re-making the side-plates ...

Look at the bright side - the gantry isn't too short :)

I think your option #1 involves the least amount of rework. After you trim the gantry beam, maybe you could fabricate a slotted mount for the side plates to allow for some adjustment.

Quick update on the progress of this build; No pics for now because I'm temporarily away from the build site (my dad's garage).

To solve my placement problems, I decided to buy larger rails and went with chromed 1-5/16" diameter closet rod. I was going to get these professionally drilled machined, but the price was prohibitive (I could have bought polished, hardened, linear rails for about the same $$ on ebay..)

In an attempt to get my holes drilled more accurately this time, I built a small table and fence for my bench-top drill press out of mdf. In addition, I changed the design of the x-rails a bit. They are now going to be drilled with 1/4" holes and fully supported with 1/2"x1/2"x1/16" aluminum channel. Because the channel is so thin, I have added cross-screws to prevent the channel legs from drifting apart when the rails are tightened to the frame.

While I was taking a break from drillling, my dad lowered the garage door on my drill press by accident :drowning:. Long story short, the drive pulley ended up cracked and the top motor housing bent badly. Too close to give up, I duck taped the dern thing together for the few holes that remained... The rails came out better than I had expected, with fairly co-linear holes!!

I quickly tested the rails on the frame, and the gantry now fits like a GLOVE! Yeah - I'm back in business!! :banana:

Because of the new rail design, however, I have lost the ability to vertically adjust the rails. My existing frame is fairly flat, but there is a .008" dip in one area. I guess I could shim, but I have decided to epoxy level the frame before bolting the rails down. This will get the x-rails level and co-planar to within .001". It's going to be somewhat of a challenge coming up with a technique for damming up the frame for the leveling epoxy, given that I have eight 1/2" holes drilled into each rail support already. I'm currently waiting for the epoxy to arrive.

I'm back at my Dad's today and took a couple of pics of the progress - or lack thereof ... :)

I just noticed that becuase of the orientation of the nuts on the rail studs (pic 5), the corners of the nuts will dig into the legs of the rail support (pic 6). I will need to grind the nuts down to avoid this for fear of causing the rail supports to bend and conform to my uneven drilling on the rails.

PICS:

1) Drill Press table I made to support rail drilling. An aluminum c-channel was clamped to the table to use as a fence for drilling.
2,3) Drill press damage when the garage door was closed onto it (nuts).
4) Drilled rail - staighter than before.
5) Nut orientation to ensure cross-screws in the aluminum channel don't hit them.
6) Rail support with cross-screws to prevent channel leg spreading.

The epoxy arrived today but I am debating as to whether to actually use it or not. The rails are only off about .007" and I'm considering moving forward with the build and revisiting this during the fine tuning phase. What say you all?

Why oh why didn't someone dissuade me from using epoxy :drowning:...

Took about 4 hours and set up the machine for epoxy leveling the rails last night. I bought a new $80 level and shims to get the rails as flat as I could before pouring the epoxy. I was rather nervous because I had never used epoxy for leveling before and was worried if the epoxy would wet the entire surface and level effectively. The good news is that the epoxy leveled fantastically! Read on for the bad news...

The epoxy that I had used in the past had the viscosity of corn syrup or honey so I built the epoxy damming accordingly. I used planks of wood wrapped with saran wrap and packing tape on the long sides of the rail, and oil-based modelling clay on the ends. I had read that modelling clay is often used in this application effectively. I blocked the pre-drilled rail holes with wooden dowels wrapped with packing tape. I also liberally applied vaseline to all areas I did not want the epoxy to stick - as you can imagine, it was a very messy operation. Although I was somewhat worried about leakage, I reasoned that the surface tension of the epoxy would prevent it from seeping under the dam walls. That assumption would prove fatal.

The epoxy I ordered was from www.jgreer.com, and I have nothing but praise for it. It mixed and leveled wonderfully, took a LONG time to kick off, and had no trace of amine blush. This epoxy, when mixed, has the consistency of olive oil - VERY THIN. I calculated I needed 3/4 cup for each rail to create a 1/4" depth pad of epoxy. Trepidatiosly, I mixed a batch and poured it in with the help of my brother. Almost immediately, it leveled perfectly. The pour took all of about 30 seconds per rail!

So while I sat there with my brother shooting the crap after a successful pour, he suddenly asked me - "hey, did you drop a little epoxy off the rails?" I replied that "I might have..." when simultaneously, both of us noticed a growing pool of epoxy on the table!!

Immediately - panic set in!!! Both my brother and I went around the frame like frantic chickens attempting to plug multiple leaks with the remaining modelling clay. At the same time, we were trying to sop up the growing pool of epoxy that was starting to gush out, seeking to prevent the frame from being epoxied to the table :(. If any of you have ever tried to clean up spilled epoxy, you know what a pain in the A$$ it is.

Long story short - I spend the next four hours with a roll of paper and acetone, wiping away drips. Did I mention this epoxy remains liquid for a LONG time? After going to bed at 1:00AM and spending a mostly sleepless night wondering about the outcome, I awoke at 5:30AM to check the rails. Still the consistency of sap. I wiped the excess drips and went back to sleep till noon.

I awoke and went straight to check the progress... The epoxy pads were partially set enought to remove the damming. This was the easiest part of the whole thing. Thanks to the vaseline, everything came off very easily. The pad was glass flat except for a meniscus at the edges and around the dowels. These, I thought, could be carefully ground off later to get a perfecly flat pad. When I went to check the other rail, however, it was clear that a LOT more epoxy leaked from this rail - the pad was about half the thickness (1/8")...

PICS:
1) Shimming everything flat
2) Damming
3) After the pour
4) Closeup of the modelling clay dam. The edges are where the leaks occured. I should have pressd modelling clay into the unwelded edges of the steel tubing; there was a venturi effect there that caused epoxy to continue being sucked out of the dam.
5,6) Epoxy pad after dam removed.

After some deliberation, I decided to strip the epoxy pads off. Spent most of the afternoon scraping the partially-cured epoxy pads off the frame; they came off in one piece like a floor matt. I set them aside on spare pieces of steel tube so I may use them later (somehow :) ). I still have 3/4 of the unmixed epoxy available if I decide to lay down "confromal shimming" later ... but it seems to be more of a pain than it is worth. Currently, my rails are only off dead straight by a max of about .007" - that can be handled with shimming. If I were to pour epoxy again, I'd still have to grind the meniscus points off to have a dead-flat surface. Given the multitude of other errors that this machine has (skate bearing slop, eccentric pullies, non-circular idlers, etc...) I don't think the difference in accuracy will be missed. Worst comes to worst, I can always use the epoxy later if I feel the results will be warranted.

PICS:
1) Epoxy remaining.
2) Epoxy used
3) Removed epoxy pads. Blue object is my new level.
4,5) Gantry on new rails.
6) Bearings now hugging rails.

Worked a bit on the cnc day before yesterday, and I'm just about gettin to the point where it is starting to look like a real machine! Hopefully, the build should go fairly quickly now, unless Murphy decides to visit me again...

I mounted and aligned the rails on the frame, and finished the bearing assemblies to allow the gantry to ride the rails. From the look of things, it doesn't seem like epoxy leveling will be necessary - the gantry rides fails easily on the rails. It ain't butter, but the slight hesitation during motion is most likely due to the endplates flexing. This should cease to be a problem when the dual x-belts are installed. If necessary, I have also made arrangements to beef up the endplate/gantry beam connection.

Up next will be installing and tensioning the x-axis belts.

PICS:
1) Rear view of the cnc with the gantry on the rails. The drive belts and stepper motors have yet to be assembled.
2) New x-rail channel supports.
3) Detail of gantry end-plate, y-axis stepper drive side.
4) Detail of x-rail bearing assembly. Inner angled bearing used to sension the end-plate to the rails.
5) Gantry beam with x-axis drive shaft.
6) Detail of z-carriage minus the z-rails.

VIDEO :)
Testing the smoothness of the bearings:

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Murphy came to visit today. David's PVC idler idea, although ingenious, doesn't seem to be working too well for me. It took an entire day to get the x-axis idlers aligned such that they are not rubbing up against the edges of the idler and excessively wandering on the pulley. My fingers are literally full of blisters from pulling the timing belts each time I tried a new configuration.

The first problem was that the studs coming off the endplates were too short to place the belts in the optimal position so that their clamps don't rub on the outside x-rail bearing. These studs have already been lock-tited into position and would be a pain to remove. I ended up getting 5/16" jam nuts and using them to retain the belt cover plate on. There are only two threads holding the plate on - hopefully it won't work loose.

The problem with the idlers is that the PVC couplers used to make them are not straight-sided; they are tapered slightly because they are compression fittings. I ended up chucking them in my drill and taking a file to them to remove some of the taper. Then, another problem reared its head - the skate bearings in the idler also have some play on the 5/16" threaded rod that they are placed on. This, again, causes the idler to not be square with the endplate, causing belt wandering. Cooger talks about an alternative set-up for the idlers on his thread, which I think I will implement down the line if I ever get this machine up and running.

As specified in the plans, the idlers are one of components that seem to me to be a weak links, but I'll reserve judgement until the machine has had a chance to run.

Murphy came to visit today. David's PVC idler idea, although ingenious, doesn't seem to be working too well for me. It took an entire day to get the x-axis idlers aligned such that they are not rubbing up against the edges of the idler and excessively wandering on the pulley. My fingers are literally full of blisters from pulling the timing belts each time I tried a new configuration.

The first problem was that the studs coming off the endplates were too short to place the belts in the optimal position so that their clamps don't rub on the outside x-rail bearing. These studs have already been lock-tited into position and would be a pain to remove. I ended up getting 5/16" jam nuts and using them to retain the belt cover plate on. There are only two threads holding the plate on - hopefully it won't work loose.

The problem with the idlers is that the PVC couplers used to make them are not straight-sided; they are tapered slightly because they are compression fittings. I ended up chucking them in my drill and taking a file to them to remove some of the taper. Then, another problem reared its head - the skate bearings in the idler also have some play on the 5/16" threaded rod that they are placed on. This, again, causes the idler to not be square with the endplate, causing belt wandering. Cooger talks about an alternative set-up for the idlers on his thread, which I think I will implement down the line if I ever get this machine up and running.

As specified in the plans, the idlers are one of components that seem to me to be a weak links, but I'll reserve judgement until the machine has had a chance to run.

The PVC pipe coupler idlers on the 25x37 plans were a problem for me also. There was a curved low spot between the bearings that were pressed inside the coupler. I turned mine in the lathe to skim off just enough to level the coupler surface. The mounting bolts had to be tweaked into alignment also. Keep in mind that the belt will run to the opposite direction that the bolt is tweaked. Mine does not wander when the belt direction reverses anymore. It wants to "climb up hill" or in other words, run toward the tighter end of the angular misalignment. Do not tighten the belt any more than is required to run the machine reliably.

CarveOne

The PVC pipe coupler idlers on the 25x37 plans were a problem for me also. There was a curved low spot between the bearings that were pressed inside the coupler. I turned mine in the lathe to skim off just enough to level the coupler surface. The mounting bolts had to be tweaked into alignment also. Keep in mind that the belt will run to the opposite direction that the bolt is tweaked. Mine does not wander when the belt direction reverses anymore. It wants to "climb up hill" or in other words, run toward the tighter end of the angular misalignment. Do not tighten the belt any more than is required to run the machine reliably.

CarveOne

Hey CarveOne,

I'm honored to have you post on this build thread. I've enjoyed your posts for some time, albeit without responding personally!

When you mention you "tweaked" the bolt, do you mean you bent it?? After a lot of mucking around, I've finally got the idlers working so that the belt doesn't ride into the flanges on the idlers. Hopefully this will work well enough without having to re-engineer the idlers. Unfortunately, a Harbor Freight drill with an eccentric chuck is the closest thing I have to a lathe :eek:.

After getting the belts set up and tensioned, the gantry has stiffened up considerably. It worries me somewhat because the connection between the gantry beam and end-plates are chintsy little 3/4" x 1/8" aluminum angle and they flex like all hell without the belts installed. I think a lot of the racking forces are being transferred directly to the belts via the pullies. Upon re-adjusting the tension, I forgot to tighten the set-screw of one of the x-pullies, and the gantry racking became extremely noticeable (probably 1/2" across the beam). With the belts on, my dial indicator shows I can only rack the beam about .01" with hand pressure ...

My concern is that these transferring forces will cause the x-pulley set-screws to slip... To deal with this, I'm currently re-designing the gantry/end-plate connection scheme. Do you think this will be worth the effort??

PICS:
1) Idler assembly. The pic is taken along the axis of the belt. Look closely and you will see that the idlers are NOT in line; this is the only way I could get the belt to not slam into the idler flanges.
2) There are only 2 set-screws resisting the cutting forces on the gantry beam.
3,4) How the end-plates are currently attached to the gantry beam front (3) and back (4). Yuck, Chintsy...
5) How I'm thinking about updating it. The angles are 3/16" aluminum and are through-bolted to the beam and end-plates with 5/16" screws. Mmmm, beefy ...
Hopefully, this will help transfer the cutting forces better by equally loading both belts even when the router is off to the edges of the beam ??

I'm not a mechanical engineer, so I'm trying to learn as I go. I would appreciate any correction/criticism if my thinking is off!(wedge)

Hey CarveOne,

I'm honored to have you post on this build thread. I've enjoyed your posts for some time, albeit without responding personally!

I'm honored that you're honored. :o Thanks much.

When you mention you "tweaked" the bolt, do you mean you bent it?? After a lot of mucking around, I've finally got the idlers working so that the belt doesn't ride into the flanges on the idlers. Hopefully this will work well enough without having to re-engineer the idlers. Unfortunately, a Harbor Freight drill with an eccentric chuck is the closest thing I have to a lathe :eek:.

That's exactly what I did. My tool of choice for this was a deep socket placed over the bolt and pull handle to act as a lever. I applied pressure in the opposite direction to the belt travel and eventually found the "sweet spot" that made the belt run correctly. The holes I drilled in the oak board was done on a drill press table that was accurately set to 90 degrees to the spindle but for whatever reason, the bolt alignments just were not perfect, so the belt wanted to wander. The idler on the 25x37 drawings is about 2" long and has no flanges. When the motor changes direction the wander was initially almost 3/4" each way from center. The tension was enough to make the 1/2-10 lead screws bow inward. I backed off on the tension and finally made everything happy. It took a while to get it right. In your photos, you don't have that much width and the alignment is much more critical because of it. One way you can tell when it is close is to run the machine and put sideways pressure on the idler bolt until you see the belt try to run in the center of the idler or at least start moving away from the flange. Initially, you don't know which direction that the alignment is in error, so try all directions and hold it there for a few moments. Eventually the belt will respond.

After getting the belts set up and tensioned, the gantry has stiffened up considerably. It worries me somewhat because the connection between the gantry beam and end-plates are chintsy little 3/4" x 1/8" aluminum angle and they flex like all hell without the belts installed. I think a lot of the racking forces are being transferred directly to the belts via the pullies. Upon re-adjusting the tension, I forgot to tighten the set-screw of one of the x-pullies, and the gantry racking became extremely noticeable (probably 1/2" across the beam). With the belts on, my dial indicator shows I can only rack the beam about .01" with hand pressure ...

My concern is that these transferring forces will cause the x-pulley set-screws to slip... To deal with this, I'm currently re-designing the gantry/end-plate connection scheme. Do you think this will be worth the effort??

Yes. The end connections are usually a weak point. On my latest machine I have considerable problems with it and have a 1/4" piece of steel angle on each end that helps a lot but is not going to be the final answer. Some kind of cable or banding system will be needed.


PICS:
1) Idler assembly. The pic is taken along the axis of the belt. Look closely and you will see that the idlers are NOT in line; this is the only way I could get the belt to not slam into the idler flanges.

You gotta do what you gotta do. Belts are sometimes not perfect either. Whatever it takes to make it run straight.

2) There are only 2 set-screws resisting the cutting forces on the gantry beam.
3,4) How the end-plates are currently attached to the gantry beam front (3) and back (4). Yuck, Chintsy... use steel angle if it helps.
5) How I'm thinking about updating it. The angles are 3/16" aluminum and are through-bolted to the beam and end-plates with 5/16" screws. Mmmm, beefy ...
Hopefully, this will help transfer the cutting forces better by equally loading both belts even when the router is off to the edges of the beam ??

I'm not a mechanical engineer, so I'm trying to learn as I go. Neither am I, but even a blind squirrel eventually finds a nut if he puts his mind to it. :D

I would appreciate any correction/criticism if my thinking is off!(wedge)

CarveOne

CarveOne,

Thanks for the thoughful and detailed response. I will have to adopt your bolt training methods if/when the need arises.

In regards to using steel angle, I was indeed going to go that route. When I went to the industrial metal supply store however, I found a nice piece of aluminum in the scrap heap for a song, so I decided to buy it. Since I am an impoverished student, price once again took precedence over rigidity :).

I think the aluminum may work well enough for this machine. Although I have not done any detailed structural calculations as yet, I did some back-of-the-envelope math. I figure this machine needs to be rigid enough only to prevent flex under the STRONGEST cutting forces that it will encounter. This will be limited by the stepper motor:

305 oz-in = 19.06 Lb-in
x Gear ratio is 4:1
x drive pulley has a radius of approximately 1 inch

So, the maximum force with which the x-beam can be pushed is:
Torque x Lever arm x Gear Ratio = 19.06 x 4 x 1 = approx 75Lbs.

The worst case will be when cutting hard materials at the edges of the router where there is a torque (rack) placed on the gantry beam. If my thinking is not completely off, The end connections only need to be rigid enough to not deflect under this load ...

My head hurts now :tired:

I figure this machine needs to be rigid enough only to prevent flex under the STRONGEST cutting forces that it will encounter. This will be limited by the stepper motor:

305 oz-in = 19.06 Lb-in
x Gear ratio is 4:1
x drive pulley has a radius of approximately 1 inch

So, the maximum force with which the x-beam can be pushed is:
Torque x Lever arm x Gear Ratio = 19.06 x 4 x 1 = approx 75Lbs.


Keep in mind that you'll only have 75 lbs of holding force. As soon as you start moving, the force will decrease with velocity. But at ver slow speeds, when you're close to max force, the spindle will probably be a limiting factor.

Keep in mind that you'll only have 75 lbs of holding force. As soon as you start moving, the force will decrease with velocity. But at ver slow speeds, when you're close to max force, the spindle will probably be a limiting factor.

Yes, the stepper motor output will decrease at higher speeds, so 75lbs would be the max force. When you say the spindle will be the limiting factor, I assume you mean that the spindle will poop out before you can place 75LBS of cutting force behind it? The spindle will not add an extra force to the holding force, will it?

When you say the spindle will be the limiting factor, I assume you mean that the spindle will poop out before you can place 75LBS of cutting force behind it?


I don't know what you're using, but yes.

I'm going to be using a Hitachi MV12 because it has a reputation for being one of the quieter routers.

Ehem ... that should be the Hitachi M12VC :stickpoke

Been hard at work for the last few days, the more I fix on the machine, the more I find needs to be fixed. Right now, the pulleys are slipping on their shafts with even hand pressure. I'm planning on drilling and tapping them for another set-screw, and filing flats on the shaft. I'm also gonna have to pull the machine apart again to paint the frame. I'm getting close to lockdown on the mechanical parts though!

A word of advice for the newbies / revelation for me :
I ordered a bulk pack of skate bearings from VXB bearings on ebay; I was always under the impression that one skate bearing equals another - WRONG! I was having extreme difficulty getting my z-axis bearings not to bind. When tensioned against the rail, there was either too much play, or they would bind... This lead to a re-build of the gantry three times with no luck in stopping the binding. After a couple of weeks out in the garage dust, my bearings had built up a ring of blackish soot around the area where they ride on the z-rails. That's when I noticed that one of the bearings' soot rings was not perfecly concentric, there seemed to be a slight "wobble" in it. On a hunch, I swapped it out. THAT made all the difference in the world. The bearings now slide like butter. That bearing was eccentric.

Lesson learned. I checked the bearings on my other axis and was shocked by what I found. A lot of them had defects. One had what seemed like a 1/16" deep pit on the outside surface. Another one had an uneven chamfer on the outside. I don't know if I got a bum batch or what, but check your bearings carefully before mounting them to your machine!

PIC: Track marks on a healthy bearing.

Worked all day today but didn't get as much done as I wanted to.

Stripped and soldered 4 female db-9 connectors for each of the x,y,z axis steppers and limit switches. These will go to the terminals on the control board. The male connectors will be soldered to the stepper leads after wire run lengths have been determined.

I also drilled and tapped the z-backplate to accomodate a k-cnc router mount. The backplate can be rotated 180 degrees for a custom mount hole pattern. The center holes on the mount are tapped #8-32 placed every 1-1/2". The outside holes are spaced out 2-1/2" every 1-1/2" and tapped for #8-32. If the plate is flipped for the k-cnc configuration, the bottom #10-32 holes will match the spacing of the off-the-shelf mount. The center holes can be used to mount a pen, glass cutter, wood burner, etc. The four holes on the corners are tapped 1/4-28 and can be used to hold sundries such as the vac system.
I also attached mechanical limit stops to the z-axis; because of the belts, the router drops to the table forcefully when power is removed.

I had been having problems with the pulleys slipping. I took them out and filed flats on the shaft where the existing set-screws were and drilled & tapped and second set-screw - hopefully this will prevent the slipping. There are still a few more pulleys that need to be completed.

Getting closer.

PICS:
1) Newly drilled and tapped z-backplate.
2) Backplate unbolted to the z-rails
3) k2-cnc router mount orientation
4) Extra pulley set-screw drilled
5) Shaft indents for set-screws
6) Z-axis assembled. Note the screw that limits the upper and lower range of motion.

Took apart the machine today to paint the frame. Took the rest of the day and went shopping for the stepper wire and electrical components of the system. Its lots of fun to wait for paint to dry :).

Hey Sonic,

Haven't checked in for a while, but it looks like you've made very good progress.

I had a couple of winners in the VXB lot, too but after getting another pack of them (they are still pretty cheap) I found a set of usable ones with a couple of spares.

I did have some trouble with the PVC coupler idlers - I tried using the gray electrical ones. When I used the white irrigation ones, which have slightly different dimensions, I found they were much easier to work with, and sanded smooth and straight so the belt says where it should.

The work you are doing to make sure the set screws stay put will pay off. The only material I've ruined is due to either those things slipping (they won't anymore!) or my own stupid lack of origin placement. (You can fix the machine, but you can't fix stupid!)

Can't wait until you get to movement!

Hey Sonic,

Haven't checked in for a while, but it looks like you've made very good progress.

I had a couple of winners in the VXB lot, too but after getting another pack of them (they are still pretty cheap) I found a set of usable ones with a couple of spares.

I did have some trouble with the PVC coupler idlers - I tried using the gray electrical ones. When I used the white irrigation ones, which have slightly different dimensions, I found they were much easier to work with, and sanded smooth and straight so the belt says where it should.

The work you are doing to make sure the set screws stay put will pay off. The only material I've ruined is due to either those things slipping (they won't anymore!) or my own stupid lack of origin placement. (You can fix the machine, but you can't fix stupid!)

Can't wait until you get to movement!

Thanks for checking in, Rev - motion should be only a week or two off. I've currently got the machine in pieces to paint the frame, and beef up some areas that I though would be weak points (gantry/end-plate connection, pulleys). Just thought that I'd mention that your site (www.liming.org/cnc) has been a great reference for me in this build. Your machine seems to be a slightly more recent version than mine, so it has been useful to see how things have evolved in the design.

I'm taking my time putting this thing together right, because I don't want to have to do it again for a while! I'm starting my Master's Degree in Computer Science this September, so I doubt I will have the time to attempt another build for a few years.

You an IT kinda guy? I spent 25 years in the computer industry - started when we communicated with them by punching little holes in cardboard. Toggled switches on the cpu to load the loader. My kids hear that and they roll their eyes, having never seen such a thing.

Anyway, it does appear you are doing your table very right - what software you been eyeing for it?

My background is in Electrical Engineering, but I have been doing a lot of coding in the past few years - mostly Actionscript 3.0, Java, and C++. Prior to that, I made my living in the entertainment industry for 15 years. I'm going back to school full-time to update my professional credentials during this economic lull - hopefully things will have picked up by the time I finish.

In terms of software, MACH3 of course is obligatory, but I'm still considering CAD an CAM options. I know Sketch-Up pretty well and have gotten pretty fast at using it, although generating g-code directly from it is somewhat of a pain. Apparently someone wrote a plugin for it in Ruby that will generate g-code, but I am unsure of how well it works. I'm also considering Rhino, but the learning curve will be significant. Vectric software seems to have a huge following here, so I will have to check them out as well.

So many options, so little time!

Lots to report since the last update! I've been busy building, so my updates have been a little lax; sorry to the 2.5 zoners who are faithfully subscribed to the thread :).

I did decide to reinforce the gantry beam/end plate connections as described a few posts ago. Although this did cut down on the flex, the gantry beam STILL flexes under heavy racking force (exerted by hand). I'm not sure how much of an improvement I will actually see in cutting, but it is most certainly a sturdier connection than was specified in the plans. No harm - no foul.

Installed all the remaining belts and pulleys. I also finished soldering the limit switch wiring, and ran the electrical connections as neatly as I could using LOTS of zip-ties. I have yet to hook up my limit switches; I ran shielded 2-conductor cabling, but had to bundle the limit and stepper wiring together on the z-axis. Hopefully, there wont be too much noise induced on the limit lines. I have some filtering capacitors waiting, just in case. For those of you who have ordered the cheapo Ebay limit switches, be warned: the plastic on these melt VERY quickly and will DESTROY the limit switch mechanism. If the soldering terminal gets too hot, it will casue the spring tensioning mechanism in the switch to get out of whack, destroying the switch. I buggered 4 switches doing this. DO NOT LET THE SOLDER TOUCH THE PLASTIC NEAR THE TERMINAL EVER. Amazingly, I didn't have this problem with the American-Made limit switches I went and bought at $3.99 a pop ... :rolleyes:

I'm gonna have to post the motion video later today because I got socked with a $496 traffic ticket last week. The next three days are going to be spent doing community service. Oh joy.

PICS:
1,2) Endplate beef-up. Note limit switch on gantry.
3) Belt tensioning mechanism and y limit switch mount.
4) Cables and zip ties. The control board and computer is under the table.
5) Z-axis cable organization. Limit and stepper cables routed together.
6) Overall view.

About 95% there - still a lot to do; BUT - community service summons ...

Tell the judge that staying at home and working on your CNC machine is community service because it keeps you off the streets where you tend to get tickets. Hmmmm, maybe he/she won't go for that defense.

Maybe those switch cases were made from recycled model car plastic "trees". I knew a guy who used to build very nice custom car models. When he got tired of looking at them he set two of them on fire with lighter fluid and then pushed them together to simulate a collision. Then he blew out the fire when enough of it got melted. Melted really fast. Put them back on the display shelf for a while. Weird dude he was. He was a room mate when I was in military Electronics Tech school.

I'm not subscribed but I read your thread all the time. Tends to explain why your views counter shows more than 2.5. :)

CarveOne

You an IT kinda guy? I spent 25 years in the computer industry - started when we communicated with them by punching little holes in cardboard. Toggled switches on the cpu to load the loader. My kids hear that and they roll their eyes, having never seen such a thing.

Anyway, it does appear you are doing your table very right - what software you been eyeing for it?

I remember punch cards very well. Do you remember core memory?

CarveOne

Tell the judge that staying at home and working on your CNC machine is community service because it keeps you off the streets where you tend to get tickets. Hmmmm, maybe he/she won't go for that defense.

CarveOne

LOL! That gave me a badly needed laugh -

It's my first ticket in about 10 years so I guess I'm due. This was for taking a left hand turn on a protected red arrow - it was at 1:00AM with no traffic on the road (other than the cop, of course). It was just plain careless; I didn't notice the red arrow until I was already in the intersection - oops (nuts).

I decided to take a chance with community service since paying the $496 would cut into my college fund.

Well, I just came back from four hours of "service" at the local food bank. I figured I would be serving soup, or packing cans or something. They had me clean the rotten food slop that had missed the 10'x10'x30' monster trash bins they have outside. I swear, that thing looked like it hadn't been cleaned in MONTHS. The "food" had turned into a ten inch thick layer of gelatenous slop that required a SHOVEL and my fingers to scoop up. Underneath, was a layer of rat droppings - I kid you not! To top it all off, I had to ASK for gloves and a mask. I have a feeling OSHA would have a field day with this one ...

PS: Any Californians reading this, DO NOT GET A TRAFFIC SIGNAL TICKET, they are now more expensive than reckless driving tickets. Because of the state budget crisis, a $100 fine, after the "state fees and fines" have been added, totals close to $500.

2 more days to go!!!!

It's been a long time coming - but I finally have motion!!!!

After a day of missed steps and motor grinding, I finally happed onto the configuration in mach3 that works well. My hobbycnc driver board and motors were having trouble with all three axis loosing steps after current limiting kicked in. I read all the posts on here about the current limiting mod, and thought that might be necessary to get my machine working. But, on a whim, I tried turning on the "dir lowActive" and "step lowActive" setting on the motor control pins menu. Voila - instant smoothness!! I didn't find this configuration tip in any of my internet seachings, but it is mentioned briefly in the hobbycnc documentation. If memory serves, it reads: "our driver chips work best with active on low transitions" or something to that effect.

Anyway, here is my poorly (read non) edited footage of cnc motion!!

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What's your accel set at? It looks pretty low. Can you set it faster?

That machine is looking really good! As ger21 thinks, the acceleration/deceleration setting looks too slow.

CarveOne

The acceleration IS really slow. I think it is 3 on the x and y, and 4 on the z. I'm not really sure how to set it. I can set it very high, but it causes the table to recoil quite a bit at higher accelerations. The steppers don't poop out until I set it at about 40 or so...

What I ended up doing is running the "roadrunner" g-code sample from mach3 and adjusted the acceleration so that the motion was as smooth as possible with no table recoil. Is there a better way to do it?

So, the belts are flexing when starting and stopping? Sounds like a flaw in the design. Can you make the belts tighter?

When you start cutting, you may find that the faster the accel is set at, the better. With the accel that low, you'll rarely be able to reach your programmed feedrates. I'm still setting up my machine, but with my Y axis set at 180ipm and an accel of 12, it gets up to full speed in less than an inch. I just went out to verify that, and ended up increasing my rapids to 200ipm. Still gets there in less than an inch. Tomorrow I'll see if I can increase the accel a bit more.

So, the belts are flexing when starting and stopping? Sounds like a flaw in the design. Can you make the belts tighter?

When you start cutting, you may find that the faster the accel is set at, the better. With the accel that low, you'll rarely be able to reach your programmed feedrates. I'm still setting up my machine, but with my Y axis set at 180ipm and an accel of 12, it gets up to full speed in less than an inch. I just went out to verify that, and ended up increasing my rapids to 200ipm. Still gets there in less than an inch. Tomorrow I'll see if I can increase the accel a bit more.

Yes, I believe the belts are rebounding. I am not sure what the cnc's motion is supposed to look like because this is the first one I have ever built/seen first hand. The roadrunner motion is noticeably jerky at higher acceleration rates (above 10 or so ...) so it does appear that the belts are the culprit. I can tighten the belts some more; it will increase the friction and wear, but may reduce the rebounding. The rebounding is not noticeable when jogging, only when running the roadrunner g-code.

I'll take a video when I can show some motion at various acceleration settings. Right now, my limit switches are completely buggered by noise. I can't even get the steppers to jog; mach3 is constantly in an emergency state.

Also, I'm running 1/8 microstepping right now and thinking of upping that to 1/16. Do you think this would help with the jerkiness?

Are you in CV mode or Exact Stop mode? Try CV mode if you haven't. I think you need to try some simpler things than the roadrunner. Don't set up your machine based on that. It has lots of little movements and direction changes. It's jerky at higher settings because it's changing directions quicker. I'd try running some other code with accel at 10-15.

Changing microstepping won't effect the jerkiness.

Ger: I'm in CV mode I believe (it's the default for roadrunner?) . Anyway, the CV led in mach is lit up.

I tried fooling around with motor tuning tonight and I might have to reconsider my last comment about the belts rebounding ... I think the entire table is rebounding. I can set my x,y accelerations to 60 and this thing FLIES when air-cutting roadrunner. BUT, it will shake itself apart in no time flat. The entire enclosure shudders. At 15, the shuddering is much less, but there is noticeable vibration telegraphed to the structure. At 6, vibration is very low but detectable. At 3.5, the vibration is imperceptible.

I'm not quite sure what is going to be the best way to proceed. I can get very high accelerations without missed steps, but I am afraid of shaking the machine to death. I'm not sure how much rebounding is acceptable. My x pulleys came loose testing today, so they're being lock-tited overnight. I'll get some video tomorrow.

Worked on tuning the motors for a couple of hours. I ended up increasing my microstepping to 1/16 but was still getting jerkiness. I tried CV mode in Mach3 with no success in stopping the jerkiness. Then, on a whim, I checked "plasma mode" and wham, instant smoothness - not quite sure what it does but it allowed me to increaase my acceleration settings significantly. The structure still recoils at very high accelerations (it is the entire cnc, no just the belts), but I think I have found a good compromise between speed and vibration. What say you all?

Video: Mach3 air-cutting roadrunner scaled up 3x, feedrate x 300%

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Its looking good, when are you going to start cutting something?

Jeff...

That looks a lot better. Are you actually getting 120ipm while running that? I ran it at 90ipm last night and it stayed at 90 most of the time.

Jeff: Thanks for the compliment! It's taken me a LONG time to get this far. I guess I'm following the advice on your sig ... taking it VERY slowly! This has all been quite a learning curve for me and I'm totally clueless on things like g-code programming. I think the agenda is going to be get the cnc working like a pen plotter first so that I can learn how the machine moves and perhaps digest some g-code. There is also some more work left before I can begin cutting with a router:

1) Build a mount for my screen and keyboard so i can remove it from the worksurface.
2) Put down a cutting surface with t-slots for clamping.
3) Build a router mount
4) Finish cnc enclosure
5) Route vacuum system

4 and 5 are essential because if MDF dust gets into my dad's garage, heads will roll (mainly mine :) )

ger21: Thanks again for your salient advice. The machine is working much better now! I am actually getting a 120ipm feedrate with roadrunner. It slows down a little on the curves, as you saw, but I can get 200ipm reliably when overriding the feedrate. When cutting forces are added to the equation, we'll see how that all holds up. :)

Congrats!! First movement is a big milestone, and it looks like you've made great progress. Its Miller time, even if there is still a to-do list. (hey, there's always gonna be a list.) :cheers:

There was a period of "getting to know" the machine where setting the right/optimal parameters was important, but once figured out they fade into the background (at least, until something isn't cutting right, and then you have to re-visit it.)

Since I am perhaps a few weeks ahead of you on the learning curve of these things, allow me one bit of advice: Get a logbook where you can write down Mach3 settings, CAM settings (for whichever program you use to generate the G-code), successful feed rates on different materials for a given router bit, router speed settings, etc. etc. There are so many variables at play with this machine that I found I was loosing some experience as to what worked or didn't unless I started writing it down. (Of course, this is mostly due to my bouts of CRS disease.) Several times now I have saved myself time by being to refer to the log. Its important to write down both what does work as well as what you know does NOT work!

I think I probably obsessed about speeds until I realized that this part of the game is really only key if you are trying to create a production shop, where time is money. If you are mostly doing one or two offs, then cutting times of 1 hour vs 1 and a half hour after spending a day doing the CAD/CAM right hardly seems important.

I am still at the stage where I am fascinated by watching the thing cut! I've been told by those further along that this, too, will pass, but I hope not any time soon.

Anyway, Sonic, way to go!!

PS Carve - sure I remember core, though most couldn't afford it. I remember seeing little old ladies sitting around "sewing" those fine wires through all those little donuts to make one - and this was in New England! Nice non volatile memory - 4K at a time!

Congrats!! First movement is a big milestone, and it looks like you've made great progress. Its Miller time, even if there is still a to-do list. (hey, there's always gonna be a list.) :cheers:

There was a period of "getting to know" the machine where setting the right/optimal parameters was important, but once figured out they fade into the background (at least, until something isn't cutting right, and then you have to re-visit it.)

Since I am perhaps a few weeks ahead of you on the learning curve of these things, allow me one bit of advice: Get a logbook where you can write down Mach3 settings, CAM settings (for whichever program you use to generate the G-code), successful feed rates on different materials for a given router bit, router speed settings, etc. etc. There are so many variables at play with this machine that I found I was loosing some experience as to what worked or didn't unless I started writing it down. (Of course, this is mostly due to my bouts of CRS disease.) Several times now I have saved myself time by being to refer to the log. Its important to write down both what does work as well as what you know does NOT work!

I think I probably obsessed about speeds until I realized that this part of the game is really only key if you are trying to create a production shop, where time is money. If you are mostly doing one or two offs, then cutting times of 1 hour vs 1 and a half hour after spending a day doing the CAD/CAM right hardly seems important.

I am still at the stage where I am fascinated by watching the thing cut! I've been told by those further along that this, too, will pass, but I hope not any time soon.

Anyway, Sonic, way to go!!

PS Carve - sure I remember core, though most couldn't afford it. I remember seeing little old ladies sitting around "sewing" those fine wires through all those little donuts to make one - and this was in New England! Nice non volatile memory - 4K at a time!

Thanks a lot revwarguy! It does feel good to have this thing finally moving, but I can't wait to get cutting with it. I will heed your advice re: keeping a log book. Even with the limited exposure I have had tuning the machine, I often find myself asking "now what was that previous acceleration?" etc. Your advice will come in handy!

Since your machine is a close sibling of mine, I wanted to ask you some specific questions:

1) What velocity and accelerations did you settle on for your axis? Did you find that your whole machine jumped on direction reversals with higher accelerations? My gantry is about 80 Lbs so that could be part of it ... Does having lower acceleration setting affect anything other than the speed of the cut? Does a lower acceleration create any anamolies or prevent you from doing certain types of cuts??

2) How did you go about ensuring that x was square to [y,z] , y was square to [x,z], and z was square to [x,y] ? Since the rails don't share any common planes (they're offset from one another), a simple try-square doesn't seem to work. After I get my list above squared away (pun intended), I'm going to square my axis as best I can.

I often visit your site for reference and inspiration. Have you made any improvements to your machine? Cut any cool new things with it?

PS: What is CRS?? I have never heard of it ...

Does having lower acceleration setting affect anything other than the speed of the cut? Does a lower acceleration create any anamolies or prevent you from doing certain types of cuts??


It can. When in CV mode, lower acceleration can result in corner rounding. The faster the accel, the less this is a factor. Also, accel can have a large affect on velocity when doing 3D carving.

To square the axis, cut and measure some square parts. Adjust as needed.

Hey Sonic,

Since your machine is a close sibling of mine, I wanted to ask you some specific questions:

1) What velocity and accelerations did you settle on for your axis?

I started in the middle of the Mach 3 band, and started increasing the velocity until one of the steppers stalled while jogging around the patch. Then I executed some complex G-code (something with curves in various directions - the roadrunner will do) and found I had to lower it a bit more to prevent stalling. This I left for the velocity setting.

I must admit I do not have a good way to set the acceleration, and it seems that this is the most important as far as cut time is concerned, since the router will spend 80-90% of its time in acel/decel mode rather than going full speed to a position. Perhaps someone with more experience could chime in... I just increased the acceleration until it seemed (by noise, mostly) to be safe for the router and the table.

This is mostly moot, however, because you will learn that you will want to lower these values when you start cutting something, unless it's foam or something like that (haven't tried foam yet.) When you first cut a new material, you will have experiment to see what speeds work best.

Did you find that your whole machine jumped on direction reversals with higher accelerations? My gantry is about 80 Lbs so that could be part of it ... Does having lower acceleration setting affect anything other than the speed of the cut? Does a lower acceleration create any anamolies or prevent you from doing certain types of cuts??

Yes, if you set the acceleration too high, the machine will jerk about. Low speeds or accelerations may cause the bit to gum up or clog up, or it could burn the material if the spindle speed is high, but in general lower speeds seem to be easier when cutting rough out passes, and you can raise the speed on fine finish passes.

2) How did you go about ensuring that x was square to [y,z] , y was square to [x,z], and z was square to [x,y] ? Since the rails don't share any common planes (they're offset from one another), a simple try-square doesn't seem to work. After I get my list above squared away (pun intended), I'm going to square my axis as best I can.


I just used a large square that I "calibrated" - the old "draw two lines with it flipped for one of them" trick. When running I put a dial indicator on the router mount and made passes keeping two axies constant, watching the face. Shims or bolt adjustments were then used to fine tune. The base of the table was off more than anything, and I just placed shim material under the plywood spacers to make it flat according to the dial. That way I can just put a new sheet of sacrifice fiber board down. If I am doing something that needs to really be on the money, I can make a pass over the whole sacrifice board with an endmill.

Have you made any improvements to your machine? Cut any cool new things with it?

Been vacationing and family stuff mostly. I have cut a few things, but I haven't updated the website yet.

PS: What is CRS?? I have never heard of it ...

CRS = Can't Remember S**t disease :o

Hey Sonic,

PS: What is CRS?? I have never heard of it ...

CRS = Can't Remember S**t disease :o

OMG, it must be going around cause I, myself, have a bad case of it :drowning:! Seriously, thanks for the feedback.

I am chipping away at my cnc-to-do list and welded up the monitor and keyboard brackets today. A coat of hammered Rustoleum is drying on them as I write this. It's amazing how crappy stick welds can look when you're in a hurry to complete things! Needless to say, I WONT be taking any close-ups of these particular brackets hehehe ...

PICS:

1) CAD concept drawing, arms swung out while in use.
2) Back view of mount while swung out.
3) View when folded flat for storage.
4) Keyboard and Monitor mounts.
5) "Close-up" of monitor mount. Holes are VESA standard - paintjob and welds are crappy :)

Got the monitor and keyboard mounts up a few days ago, but am only getting a chance to post now. It was 105 Degrees in Southern California last week, and I had to be fully clad in protective clothing while welding - not the most comfortable scenario. Needless to say, all question of accuracy and good welds went out the window at these temperatures - I eyeballed everything. As a result, my monitor and keyboard are only perfectly level at the work position, when swung back in their storage position, they are crooked. But hey, they work and I have nothing on my worksurface now - woohoo!!

PICS:
1) View from work position
2) Guts of the mount from the back
3) Overall view
4) Monitor and keyboard can be swung 270 degrees around to store flush with the enclosure box, or to change the monitor viewing position. Here, the monitor faces the garage entryway door so I can check the status of a job from inside the house.

I seem to remember reading that overriding your machine in Mach will override everything.. Meaning if you have maxed out comfortable speeds and acceleration in the motor tuning then bump up the override on the main display you can exceed the accelerations you set in your motor configuration.

As a guideline I set all my programs on the aggressive side for speeds and only use the Mach override to reduce things.

Double check this if interested, I'm dusting cobwebs off old memories and am not completely sure if I'm correct.

Mil

I seem to remember reading that overriding your machine in Mach will override everything.. Meaning if you have maxed out comfortable speeds and acceleration in the motor tuning then bump up the override on the main display you can exceed the accelerations you set in your motor configuration.



Newer versions have separate override for rapids, although you can link them together if you want. This was changed about a year or so ago.

Sonic,

Love those mounts for the monitor and keyboard - its enough to make me want to learn to weld! Your machine is looking very good.
Are you going put up some plexiglass or ? sides around the upper frame to keep the swarf on the table? I cut some PVC for the cable chain, and that stuff went everywhere, but I did nothing to stop it. I am definitely going to add something like that for mine - I don't think you'll need a top cover if you plan on putting a vacuum collar in there as well,

A few messages ago I wondered if there was someone more experienced who had a better or just plain different method than TSAR (That Sounds About Right) for tuning the acceleration setting in Mach 3. Anybody want to help here? Ger21? Carveone?

Its been great here - 50's at night, upper 70's day. Unusual for St. Louis at this time of year. Stay cool :cool:

Sonic,

Love those mounts for the monitor and keyboard - its enough to make me want to learn to weld! Your machine is looking very good.
Are you going put up some plexiglass or ? sides around the upper frame to keep the swarf on the table? I cut some PVC for the cable chain, and that stuff went everywhere, but I did nothing to stop it. I am definitely going to add something like that for mine - I don't think you'll need a top cover if you plan on putting a vacuum collar in there as well,

A few messages ago I wondered if there was someone more experienced who had a better or just plain different method than TSAR (That Sounds About Right) for tuning the acceleration setting in Mach 3. Anybody want to help here? Ger21? Carveone?

Its been great here - 50's at night, upper 70's day. Unusual for St. Louis at this time of year. Stay cool :cool:

Thanks for the kind words rev!

I learned to stick weld specifically for this project, although I did the obligatory "welding cart" before taking on the cnc frame. It's actually not too bad once you get the hang of it. If you have access to a mig welder, you could probably stick things together (non structural) within a couple of hours of starting. I got my Lincoln Tombstone welder off craig's list for $65. The guy wanted $100, but it looked like it had been through a fire; the casing was fully rusted through, there was no back, and there were mudworm tunnels in the tranformer!! It's a circa 1966 welder. Things back then were made to last - still welds like a champ.

This summer has been very temperate in Socal, except for the last week of heatwave. Usually, September is the hottest weather for about 2 weeks, and then things cool down. Unfortunately for me, they will cool down just in time for me to start at UCLA :(.

I'm gonna be boxing the whole dern thing in when I get cutting, but will probably also put up side shields to prevent the belts and rails from getting junked up. I was considering leaving them off to accomodate oversized stock...

On a side note: I am completely clueless about tooling. What bits should I get (budget minded) to start out with? I need to mill the table flat, and then do some signage in MDF and Plastic. Will be cutting aluminum after I get the hang of things.

I finally mounted my router and put a worksurface down on the nc. That k2-cnc router mount is dandy. They are local to me, and I actually took a trip to the facility to pick it up. While there, I checked out some of the routers in back. The little one that I saw working was hauling some major A**. No spindle on it yet, but the thing was bouncing and jerking all over the place. There is a lot more flex on those machines than my homebuilt - makes me feel like I'm in the right ballpark.

PICS:
1) K2cnc mount had to be attached to a mount plate before attaching to the z-car backplate. This will serve 2 purposes; it will allow me to move the entire router mount up and was necessary to prevent from hitting the z-bearings. That z-car is tee-ight ... :)
2) Overall of z-car.

I'm gonna be boxing the whole dern thing in when I get cutting, but will probably also put up side shields to prevent the belts and rails from getting junked up. I was considering leaving them off to accomodate oversized stock...

Yup, I'm gonna make my side walls removable so that if I need to do large pieces I can, but most of the time things will fit inside. My rails are high enough that nothing seems to stay there, so I am not going to worry about some kind of shield for them yet.

On a side note: I am completely clueless about tooling. What bits should I get (budget minded) to start out with? I need to mill the table flat, and then do some signage in MDF and Plastic. Will be cutting aluminum after I get the hang of things.

Well, keep in mind I only have a couple of months experience ahead of you, but I think you need:

"MDF signage" :

a good 90 and 60 degree V bit. Also, a 1/8 and 1/4 straight bit or end mill (just so long as you can plunge the bit) for clearing flat areas. All with shanks to fit your router of course. I am using VCarvePro and I really do like the package.

If you are gonna do any 3D relief type carving, then a 1/16 and a 1/8 ball nose bit will do well, the large for the rough passes, and small for the final detail pass.

Plastic (gonna get some "Hello, My Name is Sonicwonder" action, eh?) :wave:

Go to a local sign shop that will sell you the laminated plastic, (as well as the lapel pins to glue on the back for name tags) and talk with them about thicknesses, etc. Pick their brain as much as possible - I went with pictures of my machine and they warmed up immediately - they sold me "scrap" that were many pieces large enough for my needs for next to nothing.

As to a bit for name tag sized signs, start with a 30 degree .010 bottom edge. You will then get a feel for how big to make this (depends on the font size you will be doing, and the detail you need.) These bits look like:

http://www.techno-isel.com/tooling/EngravingBits/Engraving-Bit.jpg

For aluminum, you need endmills, and a way to control the speed of your router, but I don't have enough experience there yet.

Rev.

Thanks for the heads up on router bits Rev. So it sounds like I'll need:

1) 1/8" 2-flute straight bit
2) 1/8" ball-nose bit
3) 1/4" 2-flute straight bit
4) 1/4" ball-nose bit
5) 60 degree v-bit
6) 90 degree v-bit
7) 1/16" ball-nose bit

I can see that tooling is going to rack up the cost of operation pretty quickly :(.

There are obviously many variables, but does anyone know how long these bits will last in mdf?? Say I run ten hours a week or so ... are we looking at lifetimes of months or years?? This will give me an idea of how much I can afford to spend on toolage right off the bat.

Oh, and while I'm on the subject, will a 1/4" straight bit suffice for milling my worksurface flat? I ned to skim off a couple of hundreths to level everything.

Worked on creating a pen holder yesterday. Used some scrap cutting board plastic and a 1" x1"x1/8" piece of aluminum angle drilled and tapped to create the holder. The K2cnc router mount has wider holes on the back which were not being utilized so I screwed the pen mount to those. This will be a permanent fixture on the machine so I can run dry "pen-runs" of g-code to make sure the machine doesn't blow up :).

PICS:
1) z-car with pen mount installed.
2) Closeup of pen mount. The outside plate acts as a clamp to hold pens of different diamteters. There are 2 through-holes drilled to diameters of .290 (pencil) and .320 (bic pen). Oversized pens can be accomodated by using longer clamp screws.
3) Pen mount attached to k2cnc mount with aluminum angle. All holes on angle tapped #8-32 for ease of mounting. It's very tight back there -
4) There is a "slight" bit on flex on a bic ... :)
5) My solution to the flex will be to sheath the pen in a brass tube. I could also reduce the stickout from the pen mount, but that would necessitate me removing the router everytime I want to use a pen ... kinda defeats the purpose.

Note: there is a plastic block underneath my collet. This is necessary to prevent ruining the pen because the z-plate automatically drops to the worksurface when stepper power is turned off (belts don't provide sufficient friction to hold the router in place).

My cnc seems to like cartoons :rainfro:.

In doing some testing, I might need to square my x and y axis better. I'm going to try creating some larger squares with a stiffer pen to make sure it's not due to pen-flex ...

PICS:
1,2) First plots with the pen mount.

There are obviously many variables, but does anyone know how long these bits will last in mdf?? Say I run ten hours a week or so ... are we looking at lifetimes of months or years?? This will give me an idea of how much I can afford to spend on toolage right off the bat.

Oh, and while I'm on the subject, will a 1/4" straight bit suffice for milling my worksurface flat? I ned to skim off a couple of hundreths to level everything.

MDF dulls tools pretty quick. You could be looking at a lifetime of days. :eek: Really depends on what you're doing with them, though.

Keep the rpm's low, and the feedrate high, if you want your bits to last as long as possible.

You can surface the table with 1/4" tool, but a 1" tool will do it 4 times faster. :)

Maybe a retractable spring loaded pen mechanism.

Maybe a retractable spring loaded pen mechanism.

Yeah, that would have been nice, but it complicated the construction a bit too much for me. I'm trying to do it quick and dirty because school starts in another 2 weeks. Even though the table is not surfaced as yet, I can put a few sheets of paper underneath and plot with a ballpoint pen. Over the area of a sheet of paper, the difference in height is negligible and a ball-point pen works fine.

MDF dulls tools pretty quick. You could be looking at a lifetime of days. :eek: Really depends on what you're doing with them, though.

Keep the rpm's low, and the feedrate high, if you want your bits to last as long as possible.



DAYS!!??!!

You mean I'm going to be shelling out $20 every couple of jobs for new tooling ... ?? :eek:

Hand tools are starting to look more attractive the deeper I get embroiled in this project ... :D


You can surface the table with 1/4" tool, but a 1" tool will do it 4 times faster. :)


I hear about people using "end-mills" to surface their tables, but I thought they were only for metal? I also read about "fly-cutting" and the only fly-cutting I've done is in biology class as a freshman. Care to enlighten?

Again, how long a tool lasts depends on how your using it, and what you're cutting. How long you choose to use a dull bit is up to you. Also, you can get bits sharpened and reuse them. Carbide tipped straight bits can usually be sharpened for $5 or less.


A lot of people call router bits end mills. A lot of people use endmills on their routers, since they're cheaply available.

A flycutter is a metalworking cutter for surfacing large areas. Yo u get large spoilboard surfacing bits, but they're expensive. Cheapest thing is to get the largest 2 flute carbide tipped router bit you can find, usually about 1-1/2"

http://www.amanatool.com/cncroutingdetails/rc-2257.html
http://www.amanatool.com/cncroutingdetails/rc-2252.html
http://www.vortextool.com/index.cfm?fuseaction=category.display&category_id=106

http://www.amanatool.com/cncroutingdetails/rc-2257.html
http://www.amanatool.com/cncroutingdetails/rc-2252.html
http://www.vortextool.com/index.cfm?fuseaction=category.display&category_id=106

Wow! Ignorance is bliss (at least for the wallet) ...

Some serious sticker shock going on here. Well, I guess I should've know when I spent $2K building a machine that another $2K in running costs was inevitably to follow :).

Well, in the absence of router bits, I have the world's most over-priced printer :rainfro:.

Here she is plotting in real-time:

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She's living up to her papa's nick - I love the music she makes! :cool:

Sonic,

Great looking machine. I've enjoyed the thread and respect your dedication. You'll get a lot of enjoyment out of it, but it sure does take time to get everything "finished". I'm not honestly sure any DIY machine is ever really finished!

I've been using this bit to clean my MDF spoil board. It's only 1.5" in diameter, but leaves a really good surface. I cut a fair amount of MDF and find that the carbide bits hold up pretty well. Tooling will add up quickly, but I haven't worn out any bits cutting plywood or MDF (yet). Even so, I actually mark some bits specifically for MDF, so that I'm sure I'm using my sharpest bits in solid wood.

http://www.grizzly.com/products/Bottom-Cleaning-Bit-1-2-Shank-1-1-2-Dia-/C1261

I'm wondering if you have you gotten your limits hooked up yet? I had some serious noise issues that caused false triggers on my limits. Even after swapping out ALL my wiring for shielded cable, I still had intermittent problems. A simple low pass filter (capacitor) solved that once and for all. I should have just bought a better break out board to begin with!

Steve

Sonic,

Great looking machine. I've enjoyed the thread and respect your dedication. You'll get a lot of enjoyment out of it, but it sure does take time to get everything "finished". I'm not honestly sure any DIY machine is ever really finished!

I've been using this bit to clean my MDF spoil board. It's only 1.5" in diameter, but leaves a really good surface. I cut a fair amount of MDF and find that the carbide bits hold up pretty well. Tooling will add up quickly, but I haven't worn out any bits cutting plywood or MDF (yet). Even so, I actually mark some bits specifically for MDF, so that I'm sure I'm using my sharpest bits in solid wood.

http://www.grizzly.com/products/Bottom-Cleaning-Bit-1-2-Shank-1-1-2-Dia-/C1261

I'm wondering if you have you gotten your limits hooked up yet? I had some serious noise issues that caused false triggers on my limits. Even after swapping out ALL my wiring for shielded cable, I still had intermittent problems. A simple low pass filter (capacitor) solved that once and for all. I should have just bought a better break out board to begin with!

Steve

Glad you found the thread! I was just about to pm you a link :).

Re: Limits. Yes, they are operational. I too had LOTS of noise on the limit lines, even with shielded wiring on the limit switches. A .01uF capacitor and a delay of 1000 in Mach3 seems to have taken care of the fals etriggers. I have gotten one false trigger, but it wasn't while the steppers were moving? I'm thinking I may have accidentally nicked a limit...

Thanks for the heads up on the grizzly bit - looks like it might be within my (non-existant) budget! :)

Hey Sonic,

I know its back to school time, but did you ever get something cut?

Rev

Hey Rev,

Thanks for checking in! Sadly, no :(

I'm going to have to build a dust hood as my first proj because of the whole storage-in-my-ocd-dad's-garage situation. School has been pretty rigorous, so I doubt I'll have a chance to do this till Christmas break ...

Hope things are well with you.