You got some cool ideas for sure, but to me not as impressive as the Gingery machines you built! I have the first book but still haven't worked the nerve to build my own foundry....
Hi Louie,
I am sure there are other things you are doing 'instead' of pursuing the foundry, but it is not that hard to make and it will bring you rewarding capabilities that you can probably channel for your own benefit. When you are ready, I would say just go for it!
Regards,
Wes
Hello,
I put a little time towards the carriage proto build last night and got the clamp pads drilled and tapped. The bearing clamps are now loosely mounted and ready for the final adjustment to the CRS ways for a sliding fit. It was not very difficult to set the vertical bearings by adding some shims to the carriage pads and then dropping the vertical bearing brackets down to the surface and locking them in place. I think once I get the .375" x 3.000" CRS stock I should be able to slide the carriage onto the bar and adjust the bearing clamps to the edge of the material and tighten them in place.
Once they are adjusted and bolted tight,I can drill a couple dowel holes through the clamp plates and into the pads and insert dowels to keep them in place if needed. Then it will be easy to remove them and come back to a good fit with the dowels.
I will probably make one more like this one(I will use a 2 qt. melting pot next time) for the other side of the table and then any more that I make might be a revised design to reduce the weight and (this assembled carriage weighs 5lbs 10ounces) I think I can accomplish that with a somewhat thinner wall thickness for the pattern. Dimensionally this part is good so I will not need to alter the size. I think I may do a similar carriage in a smaller size for the Y axis gantry slides but perhaps I should wait and make sure this one works good on the X axis.
I have acquired some 8020 3" square extruded tube in 48" lengths that I am planning to use for the gantry cross members and I am currently working on designing the gantry uprights to mate with these 8020 tubes. I think this tube is strong enough to use a single cross member for the gantry, but with 2 cross members it will be easier to place 2 cross slides at a good distance apart to provide better stability when cutting metals. Also I have an idea of implementing an adjustable gantry height so that I can use my 5th axis(if and when I get it finished)to work with taller objects and then lower the gantry for 2D work and items of thinner height. Have not figured out how to do it yet, but it is something else to think about.
Regards,
Wes
Hello,
Now that I have a carriage proto basically finished and ready to try I am working on the revised gantry design to implement the 3" x 48" extruded square beams that I have recently acquired. I had some preliminary drawings started for the gantry but they were basic ideas and I had not really decided what would be used for the cross members at that time. I had thought of using some square tubing but these extruded tubes with T slots are very heavy duty and should work well other than the fact that they are only 48" long. I have added some spacer tubes to the design to help widen the gantry so I will be able to clear about 52" on the table which would allow for some small clamping to be done along the edges if needed. I am not sure if I will try and cast some of the upright members or just see about obtaining some nice .5" thick flat aluminum. I would like to do at least a name plate of cast aluminum but probably will not do anything with it for some time. Here is the current gantry as I have revised it and I welcome any comments or suggestions to the design as this could be revised further before I begin the work on the uprights and spacer members. Thanks in advance for any comments or suggestions as I really value your input.
Regards,
Wes
Hello,
I have seen a lot of 4x4 builds with the CRS ways and most seem to have the ways oriented so that the 3" side is parallel to the table surface. I have the ways designed in a vertical orientation and am wondering the pros and cons to each? I had thought with them vertical there was less chance for chips and dust to accumulate on them and that the weight of the gantry would be supported by the full 3" of CRS width rather than just the .25' or .375" thickness, but upon taking another look I am thinking maybe with a good center support beneath the CRS there will be plenty of support and this way the rail has 4 bearings riding on it instead of only the one side with 2 bearings. I would really appreciate any input on this you can provide to help me decide to keep the current design or opt for the ways being parallel to the ground instead of vertical. Not too hard to change it now, but will not be so easy once I begin making the parts.
Regards,
Wes
The chief difference is that the horizontal rails have four bearings of each CNCRP carriage supporting the gantry weight, whereas the vertical rails have just two bearings supporting the gantry weight. The lower carriage just acts as a guide and supports no weight.
I have built two steel frame machines with the vertical rail configuration and both of them have been working quite well. Though the 5' x 12' machine has a total gantry weight of 185 pounds the bearings seem to support it with no noticeable wear issues on the rail or bearings. This one uses CNCRP r&p drives. The smaller 28" x 38" machine uses 1/2-10 5 start ACME lead screws. Both machines use CNCRP carriage blocks with ABEC7 bearings. As far as I know my two builds are the only ones using the vertically oriented rails with CNCRP carriages.
On the big machine I have had some trouble keeping the bottom carriage snugly against the rail. The cure for that on the smaller machine was to add two 1/4-20 set screws in the bottom edge of the gantry riser plate where they can be used to push upward against the 5/16" carriage mounting bolts while tightening the bolts. Whenever there is a reason to remove the carriages on the big machine I'll add the set screws to that machine. There is no lifting issue with big machine due to the heavy gantry.
As you mention, I do have less problems with dust and chips and it has been easy to add a shield over the rail to help with that. A few light weight airborne MDF chips will float onto the rails but I just wipe them off with a finger or 1" paint brush.
CarveOne
CarveOne
http://www.carveonecncwoodcraft.com
Hi CarveOne,
Thanks for the informative reply and for the pictures of your machines! I think with your feedback I may just continue the design and construction with the slides in this vertical orientation. Seeing your machine also shows that this may be a bit more 'streamlined' than the horizontal ways also as they do not seem to protrude as far out on each side, although my gussets will protrude a bit more unless I trim them down near the bottom.
I have another idea in regards to the gantry that I am contemplating. I want to be able to adjust the gantry clearance so that if and when I finish my 5th axis I will be able to raise the gantry for larger items. I have seen adjustable worktable systems and that might be a good option, but would it be feasible to construct the gantry uprights so that the Z height would be adjustable. I know the forces would be increased but the larger envelope would probably be used for materials that are softer and with less resistance than regular 2D and 3D work so I think it would not be too difficult. Any thoughts??
Last edited by metalworkz; 10-18-2011 at 11:16 PM.
Regards,
Wes
Hello again,
Well I finally got around to pouring the concrete in the worktable form today with my youngest sons help. It has been sitting waiting for the next step for so long I almost forgot exactly where I left off with it. It took just a little over 4.5 80lbs bags of concrete mix to fill the form so I imagine it will be somewhat over 360 lbs total weight for the combined worktable(probably close to 380 lbs with the steel angle iron and threaded rod figured in). It did not take us much more than 45 minutes to mix and pour the form including me tamping the mix into all the corners and under the threaded rod while Mike mixed the next 2 bag load. It does not look like much and I did not spend any time trying to finish the visible surface as this will be the bottom of the worktable and the top surface will be revealed after it cures and we flip it over. I forgot to mention I bought some fibers to strengthen the high strength concrete even more and the fibers could be seen in the mix as I moved it around with a trowel(looked like hairs in the mix).
When we flip it I will remove the plate that is on the current bottom and place it on the actual bottom before we set it back up on the frame platform. I am not sure how this will all come out but I figure if there are any voids in the actual top concrete surface I can fill them in with epoxy but the angle iron slats are planned to be at surface level and I will shim them up with some aluminum stock and then use the machine to cut them true prior to attaching a sacrificial work plate. I plan to have both a wooden and an aluminum sacrificial plates but I figured it would not be hard to surface the aluminum shims as opposed to trying to have a perfectly flat concrete surface. Like I said time will tell if my thinking is good or less desirable. This is definitely a fairly easy way to get a solid, strong worktable/base and cost wise it is probably cheaper and easier for most people and there are no other factors like are involved with welding a steel frame etc. I hesitate to even post a picture because it is really pretty ugly but I'm hoping the top will be much better. Now if I can keep motivated maybe this build will be finished one of these days(years!!)
Regards,
Wes
Hello,
We did some more with the concrete worktable today and it is now resting on the frame and ready for me to get to work with more of the actual machine parts. I am fairly happy with the way it turned out and I had many visions of something terribly wrong happening somewhere along the line. It was a bit cumbersome and awkward to tilt it and get it flipped but it is within the range of an engine hoist and a floor jack and we also used some jack stands to support the base while repositioning the chain and rigging. I had to jack the base up enough on one side to get the legs of the engine hoist under the base and then I was able to hoist it up vertical. I then removed the plywood bottom plate and screwed it to the other side so that would support the bottom when it is set on the frame. While steadying the base in a vertical position we changed the length of the hoist boom so that the base would lay down as far as possible and then began to lower it to about 2' off the ground and supported it with jack stands. Jacked the base up from the elevated side so the chain could be removed and then lowered it with the floor jack. Then is was just a matter of positioning straps so that the base could be hoisted up high enough to get the table under it and setting it down. If you ever attempt something like this you may find and easier way but even though it sounds a bit risky(and I would not want it falling on me or anyone else) it was manageable. For the amount of work it took I think the bang for my buck should pay off. It is definitely very solid and should do good at absorbing vibrations. I will probably do some checking to see how far off it is from flat but I am not too worried about it since I planned to add shims and a sacrificial plate that could be machined flat prior to doing any work with it. We did manage to bend a couple of the 3/8-16 threaded rods that protrude from the edges but they were going to be cut off after final assembly anyway.
It's been a long time since I started thinking this might be an option and so far it seems to be working much the way I thought....good to know that my line of thought was not too far off.
Last edited by metalworkz; 07-01-2012 at 01:27 PM.
Regards,
Wes
Hi,
Today I got the rails for the X axis drilled and mounted on the sides of the work-table. I decided to leave the rails long for now and possibly incorporate a rotary axis on the end where the rails overhang most. Leaving them long does create some problems for footprint and positioning the machine but might outweigh those problems with other capabilities. I can always cut them off if needed and it seems one always wants more travel so I opted to try and utilize as much as possible for now. I have place the carriages onto the rails and they seem to be a good fit in the current position but I need to get the gantry uprights fabricated so I can mount the gantry cross members and have the basic assembly ready to roll. There is still some minor tweaking that needs to be done but it looks like it is going together well, and the work table is very sturdy. I'm trying to keep the build moving and hopefully I can make up for some wasted time, take a look and I am always interested in your comments or suggestions.
Regards,
Wes
Hello again,
I did some more with the gantry part of the build today amounting to some test fitting and rolling tests on the rails. It is kind of trial and error at this point to get it fitted correctly and figure out my next steps for the build. I had the rack out on the rails also deciding what would be the best configuration for this build. I went with the rack mounted beneath the rail at first but may opt to go with the rack mounted horizontally to avoid the motors protruding as much along the sides of the machine as the gantry moves. I have to do some drawing and see how it will work and fit with the rest but I did get some of the exploration of configuration done. The gantry rolls very easily on the rails but if the push/pull is off at all to one side then there is some racking observed. This should not be encountered when the machine is done as both sides will be driven by individual motors slaved together. I of coarse need to fabricate the gantry uprights now but have a better idea how they will mount and what spacers will be required for the correct fit. I am getting anxious now to get the drive components figured out and assembled and get the gantry mounted.
Regards,
Wes
Hello,
I have gone over the design for he gantry end pieces several times and each time I come up with something new. Here is what I have decided to try and do for the gantry uprights. I am planning on having them laser cut from .375" thick aluminum and formed to shaped. The uprights will also serve as a carriage plate for the X axis motion. By incorporating the carriage rollers into the design I will reduce some weight and it will allow me to space the 2 rollers out to the positions I want them at without having to use the original 3/4" thick steel plates that they are on now. I think it will look better than some of my earlier ideas that utilized materials to space the ends out. I have drawn what I think is a workable sketch for the needed parts and I am attaching a snip of it here.
What do you think? Will the .375" aluminum be sturdy enough once the gussets are in place? Oh do any of you know of a finish for concrete that will go on thin and basically keep it waterproofed. I am thinking something thin that will seal the surface would be great for when I use flood coolant etc, in case it gets on the concrete plate.
Regards,
Wes
Hello all,
I have had some new thoughts about my gantry construction and a general feeling that I may be over building the cross members of the gantry unnecessarily. The cross members are very heavy wall aluminum extrusions(3" x 3") and I have now come to think that I might have plenty of strength and rigidity with only one cross member and cross slide if I utilize the carriage I have cast as a solid aluminum unit. I think the cross slide will still be very rigid with the extrusion being topped by a steel flat bar of .375" x 2.0" CRS and another .375" x 3.0" CRS strip on top of that to use as the slide. The slide will only protrude a half inch on each side of its mount and I don't believe there will be any flexing from the forces involved on those or the carriage. The Z axis will be mounted to the carriage with a .375" alum. plate to support the vertical rails and with linear rails mounted to that plate I feel there probably no way there will be any flexing or give in the assembly. I know most gantry designs are composed of 2 cross rails and also have noted design recommendations to maximize the distance between the cross rails but also feel the rigidity of this single rail will be better than some double rail designs, but I want and need some input from anyone here that cares to offer their comments, advice or suggestions about this decision. I am also planning to add some room for expansion on the height of the gantry just in case I need more Z travel or perhaps I might finish my 5th axis build and be able to use it on this machine. I think if I leave the gantry uprights the current height and just have several bolting positions for the cross beam I should be able to adjust the height with less effort when the time comes. I am posting some snips of what it might look like in the drawing for reference. Please do tell me what you think pro or con as I would like to weigh all the info before I proceed.
Regards,
Wes
Why not steel? I think you may have a difficult time bending that aluminum, and if you "miss" the angle you won't really have a second chance to bend it back.
Plus I'd think you'd want some mass in the gantry legs; with the r&p you should easily be able to movve the gantry?
Well at the least the question about the single cross member has brought up many other things that need to be taken care of also with regards to this build.
The suggestion for using steel instead of aluminum is a good one and has been tossed around prior to the idea of using aluminum. The center of the design problem lies with the length of the 3" x 3" square extruded aluminum cross members in that they are only 48" long. I want to cut a bit more than 48" in the Y direction so the Y rails will need to be about 56" long with the carriage I have cast, and that leaves the current cross beams a bit short. I have been thinking the options over for a couple weeks now and I need to move forward with this build so it comes down to spacing the cross members out to get the needed length, fabricating the gantry ends to take up the excess space, or taking the 3" square extrusions out of the equation. I am just about ready to draw up another design using a completely fabricated gantry cross beam and ends from flat stock. It will not be that difficult to make and will take all of the guess work out of the design. I will sleep on it for now
Regards,
Wes
Hello,
I have begun drawing the new design and I have taken your suggestion into consideration Louie. I have tried to include some parts of the design that were a bit unresolved like the motion mechanism for the X axis details. I feel although I will not be able to fabricate the needed parts here it will be a cleaner design and very possibly more sturdy than piecing several parts together or the angled uprights for the end pieces. I will save the extruded aluminum material for other possible builds and once the parts are fabricated it should all go together fairly quickly(if I have done it right!) The parts will be laser cut and formed at my sons shop nearby and I will still need to add as many of the known mounting hole locations as possible prior to sending to the shop. I am still working with the details but thought I should post something to bring things up to date a little. I did not get as much feedback from the previous post as I wanted but what I did get was some help so thanks a lot for the input it is always appreciated!
Regards,
Wes
I have drawn the basic idea for the X carriages to include horizontal rail clamp pads and bearings that will trap the carriage on the rails horizontally and the rollers will be positioned above and below the rail so that each carriage will be trapped on the rail and there should be no movement side to side or vertically either once the gantry is fully assembled.
I have already got the worktable spacer plates fabricated and begun to mount them to the worktable. I also got the rack mounting plates and they will need to be reamed and tapped so the rack sections can be attached to this plate and then to the outboard side of the rails. Once I removed the wood side from the wooden form I could see the angle iron I placed there leaves a very good mounting surface for the plates and rails.
I have a lot of reaming and tapping to do to get the rack plates ready so that will keep me busy for a while.
Regards,
Wes
Hello again,
I was able to get the needed hardware to mount the rack sections to the rack mounting plates this morning and started work with one side. I was able to get one side done and temporarily mounted on the machine today. I could not find the 3/8" dowel pins in a 1/2" length so I had to cut down larger dowels with a cutoff wheel in a Dremel tool. I also had a similar problem with the 5/16-18 socket head bolts and was only able to find about 12 the right length. I will cut the rest down as needed. There are 5 rack sections on each side and 2 dowels for each section, so I had to ream those 10 holes for a dowel pin press fit. The rest of the holes were reamed to a .257" Dia. for the 5/16 -18 tap and were touch countersunk prior to tapping. I feel very fortunate to have a tapping head that really saved a lot of time tapping those holes but it is not that hard to do by hand if you don't have a tapping head. I still have to add some line drilled holes at the ends of the rack mounting plates to secure them to the rail side at the ends. I sort of wish I had left the rack mounting plates the same width full length and that probably would have averted the tendency for the end to bow after laser cutting(stresses), but it will all be fine once I have it lined up and bolted down.
Regards,
Wes
Hello,
I worked with the 2nd rack plate and rack sections yesterday and today to get the plate reamed, tapped, and installed the dowels for the rack sections. I have finished attaching all of the rack sections to the plate and also installed the 2nd rail and rack assembly to the worktable side. Now I am wishing I would have made the rack plates the same width the full length. The narrow ends tend to tweak a bit since they don't have the same strength in the vertical direction but I will be adding some mounting bolts through the mtg. plate into the rail sides for both rack assemblies to position them better and secure the ends.
It still does not look like a machine but it is beginning to take shape. I think once I get the gantry legs drawn and fabricated and the cross member it will really start to look like something more than a table. Just adding the rails and the rack gives it a questionable appearance, but I feel it is all going to work out.
I am glad I decided to leave the rails full length and I am planning on using that end for 4th axis work. I guess I will have to add some fold up legs to go on the ends of the rails for some extra support but I hope that will work well for the 4th axis. Better not get too far ahead of myself as there is a lot to do yet before I can use a 4th axis.
Just one picture of where it is now.
Regards,
Wes
Hello,
I need to source the pinions to fit the rack I have installed and thought maybe someone here can help me figure out how to measure the angle or determine the correct size pinion for the rack. I read about getting the pressure angle by measuring the angle of the face of a tooth and the base of the rack but wanted to get more information if possible. Maybe the best solution will be to take a length down to a local supplier and have them match it up, but hopefully I will get more information here. Thanks for any info you can contribute!
Regards,
Wes
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