I ordered the HobbyCNC kit on Monday (4-25-05) and started building a router based off of jgro's plans. I bought 1 piece of 1/2" - 4' x 8' and 1 piece of 3/4" - 4' x 8' Blondewood Hardwood. The total was $52.00. I had the store cut both pieces in half and then started cutting them to size. I hope to have some pictures posted after the weekend.

I spent 5 Hours today cutting all the wood for my router. I managed to get the smaller cutting base glued and clamped before I ran out of brads. I found aluminium angle today at a local salvage shop priced at $9.50 / 8ft.. I also picked up a small bottle of Gorilla Glue for $5.00.

Not much time to work on the router today but I did manage to build 80% of the HobbyCNC driver (1 hour), completed the support beds and drilled all the 1.5" holes (2 hours).

The jgro plans are great. Very easy to follow so far. The only change I would suggest to anyone planning this project is that I would make the table a little larger to leave less plywood scrap. I think there is enough left over material at this point that I could have made the bed at least 2' x 4'.

This is the first time I've used the Gorilla Glue. "Wow!" is all I can say. Very strong and the expansion is great. Glad I tried it.

Here are some questions I have if anyone has answers:

1. Where is a good place to find couplings? I tried the site jgro listed but couldn't find them.
2. Should I upgrade the 1/4" threaded rod to 1/2" ACME threaded rod?
3. Can I cut the 4 3/4" grooves on the table top with the router itself?
4. Is there any reason I shouldn't make a wooden box for the electronics?
5. Would filling the gas pipe with cement to increase the rigidity be worth the effort?
6. Would a RotoZip work as the router? What are the Pros and Cons?

Not much time to work on the router today but I did manage to build 80% of the HobbyCNC driver (1 hour), completed the support beds and drilled all the 1.5" holes (2 hours).

The jgro plans are great. Very easy to follow so far. The only change I would suggest to anyone planning this project is that I would make the table a little larger to leave less plywood scrap. I think there is enough left over material at this point that I could have made the bed at least 2' x 4'.

This is the first time I've used the Gorilla Glue. "Wow!" is all I can say. Very strong and the expansion is great. Glad I tried it.

Here are some questions I have if anyone has answers:

1. Where is a good place to find couplings? I tried the site jgro listed but couldn't find them.

Have you tried cnc on a budget?
http://www.cnconabudget.com/

2. Should I upgrade the 1/4" threaded rod to 1/2" ACME threaded rod?

I used 1/4 x 20 and it works but if you are using steppers a courser thread is really better. It is hard to get speed with the 1/4 by 20 and with out some speed router bits want to burn.

3. Can I cut the 4 3/4" grooves on the table top with the router itself?
I would have to study the plans to say for sure but I suspect you could.

4. Is there any reason I shouldn't make a wooden box for the electronics?
Your call but I would go with metal I think.

5. Would filling the gas pipe with cement to increase the rigidity be worth the effort?
I don't think so at least not with out re-enfourcement in the cement.

6. Would a RotoZip work as the router? What are the Pros and Cons?

They have been used. Pros rather light and easy to obtain, Cons some questions about quality. But don't get to hung up on these details as the router is one thing that is easy to change after you get going.

I'm using a RotoZip RZ1 and like it so far.

The quality issue seems to have been with a previous design. The current RotoZip RZ1 is clearly labeled "by Bosch" and "re-engineered for improved durability and performance".

I particularly like the keyless three jaw chuck which make bit changes very easy and allows the use of drill bits up to 1/4" which is difficult with a collet system.

Pete C.

gmfoster - Thanks for the help! It was much appreciated.

WP1 - I bought my RotoZip last September and it doesn't say "by Bosch" but does have a keyless chuck. Good to hear that you've had good results. I think I'll give mine a try. Thanks.

Today's update - I bought most of the items I was missing today and yesterday. Here's a price list:

(local Surplus)
28VAC, 10.7 AMP Transformer - $22.00
(eBay)
30 8x22mm sealed bearings - $17.00
(Mouser)
1 PacTek DM-4 case - $30.00
(McMaster)
1 White Delrin Precision Ground Blank 1/2" Thick, 2" X 12" - $15.21
1 1/2"-10 Acme Size, 6' Length - $23.10
1 1/2"-10 Thread, 3' Length - $16.19
9 Plain Steel Acme 2G Hex Nut Right-Hand, 1/2"-10 Acme Size - $16.47
6 Steel Semi-Precision Ball Bearing Flanged Open for 1/2" Shaft Dia - $34.50
50 Hardened Steel Standard Dowel Pin 1/4" Diameter, 1-1/2" Length - $10.23

I still have to find the nuts and bolts and pick up the gas pipe. The total spent so far looks something like this:

Electronics - $395
CNC Router - $170

I bought the gas pipes and all of the #10 hardware last night. $40

I still need to buy Couplings and the 1/4 inch hardware.

The parts I ordered from McMaster and Mouser showed up last Thursday (5-5-2005). That night I drilled all the holes and mounted the parts for the HobbyCNC driver. I still have to wire it up but I think that its 85% complete now.

The ballbearings arrived on Friday. I bought the 1/4 hardware for $27. I also bought some material to make couplings from a salvage shop for $7.50 and the material to make the Y-axis spacers for $2.50.

The weekend was very productive but I wasn't able to complete the router. I managed to drill all the holes for the base and the gantry. I cut all the grooves in the bearing mounts and Z-Axis but still have to drill the holes. I cut all the delrin but still have to drill the holes. I cut all the alunimum and drill the pilot holes. I cut the leadscrews.
The most time consuming steps have been making the 1/2-10 ACME tap and machining the spacers. The first batch of spacers I made had to be thrown out and re-made.

I think I am about 75% complete at this point and I have to say, this is the single hardest project I have ever worked on. I have pictures but need to resize them to post. I am a little worried that everything won't turn out... but we'll have to wait and see.

[Content Removed]

The following pictures shows all of the parts cut out and drilled.

I reached a major milestone last night, I managed to finish cutting and drilling all of the parts and began construction on the various assemblies. Here are a couple of pictures that show the result.

I stole a page from Gingery when it came time to make the Anti-Backlash Block.
Here are some shots that show the process.

Here are some pictures of my failed attempt at making couplings and spacers. Only one of the three couplings shown will work. The spacers shown were re-made one at a time instead of trying to drill 4 at a time. This made a big difference. If anyone has any idea for an easy way to make 1/4" to 1/2" couplings, I'd love to hear it. I tried cnconabudget but got no reply.

I'm assuming you don't have a lathe available since that would be the best for making the couplers.

On a drill press the best procedure would be:

Load your 1/4" bit in the drill press

Clamp your blank in the vice

Center the blank as closely as possible under the bit and secure the vise on the drillpress table

Drill the 1/4" hole through the blank

Change to the next larger sized bit, say 5/16 without moving the alignment of the piece

Set the depth stop on the drill press if you want

Drill a little less than half way through the blank with the 5/16 bit

Step up to the next larger bit and repeat

Work your way up to the 1/2" bit in as small increments as possible. This will help prevent the bit from being pulled off center as it might if you went directly to the 1/2" bit due to the heavy cut. When you get to the 1/2" bit, drill the last little bit to the half way point to clean up the bottom of the hole.

This should get you about as concentric as you're going to get without a custom stepped drill bit or a lot of hassles trying to align things.

Good luck.

Pete

WP1 - Thank you very much. When I tried to make the couplers pictured, I didn't clamp the vise to the table and I jumped from 1/4" to 1/2" without stepping and moved the work piece before changing bits. I guess I have lots of room for improvement. Thanks again for the help.

I assembled the gantry last night. It doesn't slide at all but I didn't have time to adjust the blocks. I also used washers on the 3" bolts connecting the bottom plate to the gantry blocks that might give me another 1/16" of clearance. I think it will take some time to get smooth motion. Does anyone have an alignment procedure?

Ignatz, when you are mentioning couplers, I guess you are talking about from the lead screw to the motor? I use small Lovejoy spider couplers from Mcmaster Carr. It's a 3 piece assembly. You have to order each end with the proper bore that you want, then a rubber spider connects the 2. They are about $5 to $6 total for the 3 pieces.

I've heard people say that one of the best, easiest, cheapest couplers is to use clear vinyl tubing 1/2" id., just slit the 1/4" id end and join using two small hose clamps.

buscht - Thanks for the heads up. I saw those couplers and honestly for the price they seem like the way to go... but I'm not sure which I need. Which series part number are you using? I can't decide between 6408K111 and 6408K121 series.

I am using the 6408K11 series, just because they are a little smaller and the price was slightly cheaper.

buscht - Thanks man... that helped quite a bit... I stress over the little things and knowing that the smaller couplers will work is a big help.

I've attached a close up of my bearings.

I haven't posted an update in a while so its due. I have as many setbacks to report as successes. I was able to complete the general construction. All parts are cut out. All the holes have been drilled and tapped and the entire thing has been assembled (mock up). After I mocked up the machine, I found some alignment problems.
I cut the grooves in the bearing rails too shallow so I have to go back and recut them. The plans have a mistake on either DTL34 or DTL37. I cut the parts to the sizes listed in the drawing summary. Initally I thought I cut DTL34 too small but once I mocked up the machine, I found that I cut DLT37 too long.
The first 1/2-10 tap that I made didn't cut the threads deep enough, so I had to make another. I think that the key to making your own tap is: 1. The tap should be 5" - 5.5" in length. 2. The tapered section should be no more than 2" in length. 3. There should be at least 3 grooves cut. 4. The grooves should be deeper than the threads are tall. The second tap that I made worked pretty well. All in all, I question whether or not I should have spent the $45 and bought a legit tap.
I misdrilled the holes in the delrin and was unable to tap them to #10-24... so I tried #12-24. The screws fit loosely in the holes so I need to either pick a bigger screw or ???. I also have to modify the other part of the anti-backlash nut that allows the screws to simply pass through as the current .203 holes aren't big enough.
The major hold up at this point is with the HobbyCNC board. I can't get it to work properly. I've been trying to get support via the Yahoo Group but its terribly slow. It has taken almost 3 days to determine that I have burned up at least the power regulators and will have to replace parts. I'll save my review of the HobbyCNC product until after its working.

Hopefully, I will be able to report some progress sometime this week.

If you keep your eyes peeled you can get great deals on taps off Ebay. I just got a 3/4-10 plug and bottoming taps and a 1/2-20 tap delivered for about $25.

DieGuy - How did I miss the 1/2-10 tap on eBay? I've been looking for sometime now and have been able to find bigger taps (1.5") and smaller sets... but nothing with the 10TPI... I think you lucked out. Congratulations on the great find and the success story! I'll keep looking.

I found some time tonight to work on my project. I decided to fix the loose screws with plumber's tape. It firmed up the screws and I think that it just might work. I finished the grooves in the bearings. I also drilled the anti-whiplash blocks. I am going to work on mocking up the machine again to see what else I have to do.

Everything but the alignment, lead screws and electronics are done... but I think that might be the hardest part yet. I think I've made some serious mistakes.

1. The anti-backlash nuts. The ABNs that I made don't really line up right. I cut the threads in each nut seperately. When I assembled the two pieces, the threaded rod doesn't turn easily. I tried to retap the hole once the assemblies were made and that made it a little better... but not much. I'm thinking I really should have bought a real tap. How tight should the holes be? I can turn the screws by hand but its no where near as smooth as the ACME nuts that I bought.

2. I bought standard ACME threaded rod. Should I have bought Precision Threaded Rod? The plans call for 1/4" -24 threaded rod so I assumed (worst mistake possible) that I could get away with the standard parts.

3. One of the base structure's adjustment blocks has a stripped screw hole. The stripped set screw is causing me to be unable to properly align the gas pipe. I made the adjustment blocks out of harwood. I chose this material over MDF because I live in Florida and I thought the hardwood would suffer less from the humidity here. Should I remake the block out of hardwood or should I use MDF?

4. I still have no couplers. I bought clear vinyl tubing to try to make some but then found out that I should've looked for a different type of tuning (high pressure AC). Do you think that the clear vinyl tubing will work or should I look for a different solution.

I'm still waiting for my replacement voltage regulators from HobbyCNC. They shipping Wed. so I'm hoping they will show up today or tomorrow. This brings up the topic of software. Since I don't really know where to ask this question, I'll just pose it here... What CAD software is best for beginners? AutoCad? Rhino? Where should I start?

Any and all help is appreciated.

the tubbing couplers will twist on you, I use reinforced auto gas hose line with hose clamps and it works good.

Joe

It should be the really stiff hose with the reinforcing threads wound through it. That's what keeps it from twisting.

Also, keep the separation between the motor and the leadscrew as small as possible.

-- Chuck Knight

For free CAD, try http://www.A9tech.com

Hey ignatz,
It looks like your machine is coming along nicely.

1. The anti-backlash nuts. The ABNs that I made don't really line up right. I cut the threads in each nut seperately. When I assembled the two pieces, the threaded rod doesn't turn easily. I tried to retap the hole once the assemblies were made and that made it a little better... but not much. I'm thinking I really should have bought a real tap. How tight should the holes be? I can turn the screws by hand but its no where near as smooth as the ACME nuts that I bought.

3. One of the base structure's adjustment blocks has a stripped screw hole. The stripped set screw is causing me to be unable to properly align the gas pipe. I made the adjustment blocks out of harwood. I chose this material over MDF because I live in Florida and I thought the hardwood would suffer less from the humidity here. Should I remake the block out of hardwood or should I use MDF?

I think you should have tapped the pieces at the same time. Also try putting the threaded rod in a drill and running it back and forth several times. If the pieces are nylon or delrin I think freezing it first might help to as the piece would shrink then when you run the threaded rod back and forth thru it, After it warms up and expands it should be smooth.

On the stripped blocks I plan (haven't built it yet!) on epoxying nuts on the adjustment blocks along the inside of the hole. Or maybe T-Nuts...

joe2000che - Thanks very much.. that's what I thought. I have the hose clamps and returned the vinyl tubing. I think I may try making some out of aluminium before buying anything new.

chuckknigh - Thanks for the alignment tip... I'm sure it will be come in handy.

ger21 - Thanks I'll give it a try.

CNCRob - Thanks very much for the encouragement. It really helps me to not give up.

randyf1965 - I really like the idea of freezing the delrin... that just might work. Thanks! I ended up remaking the adjustment block out of hardwood. If this one busts too, I will remake them all with t-nuts. I think that if you use MDF to make the blocks, you'll be fine with just threads but if you use hardwood, then maybe the t-nut are the way to go.

More ups and downs over the weekend. I got the HobbyCNC board working (well mostly, haven't actually connected steppers to it but I didn't get my voltages worked out and the drivers soldered on). I remade the adjustment block out of hardwood because I have so much scrap on-hand. I found out that I miscut dtl34 so that the threaded rod doesn't align properly. I'll have to remake them... but that's okay because I cut them at 3.0" instead of 3.25" (due to a description/drawing disagreement) so I'll get to fix that issue. I managed to build a PC from spare parts I had laying around. I made a simple table for the router from an old solid core door I had laying around on top of some saw horses.

I have a couple of questions:

1. Is the assy04 connected to the base support structures? How?
2. Are the base supports connected to dtl05? How?
3. What is the single wood screw used for?
4. Will the PC I built (Pentium 233 98MB RAM Win98) be sufficent? Will it run TurboCNC in Windows or should I plan on running DOS?
5. Once I have the machine completely assembled, what's the best way to adjust it? Do I simply level all the gas pipes and then use a dial indicator to make sure that they are equal difference apart?
6. Is there a premade TurboCNC configuration file that works with a HobbyCNC 4UAPC?
7. Is there some G-Code that I should use to test the machine once its assembled, adjusted and configured?
8. Do you have any good ideas/plans for a stand/cart for the router and PC?

4) TurboCNC must always be run in DOS. With Win98, yuo can use Start>Shutdown>restart in MS-DOS mode.

6) I don't think so. It's a good idea to set it up for your machine, as ports can be different, and accel and velocity settings are machine specific.

4) TurboCNC must always be run in DOS. With Win98, yuo can use Start>Shutdown>restart in MS-DOS mode.


Really? I thought it just needed direct Parrallel port access... meaning DOS, Win95 or Win98? Did I mis-understand the requirements?

Really? I thought it just needed direct Parrallel port access... meaning DOS, Win95 or Win98? Did I mis-understand the requirements?

486-66 PC or better with math coprocessor
DOS or DOS base operating system (or WIN 3.1, 95/98)
Available parallel port for IO

NOTE: Direct port access is not permitted under Windows NT, 2000, and XP, and so the proper function of TurboCNC with these operating systems is not a given. Instructions on how to set up these systems with a boot disk is included in the program documentation.


My impression would be that it runs under 95/98 also, but not an NT type system.

Joe

Really? I thought it just needed direct Parrallel port access... meaning DOS, Win95 or Win98? Did I mis-understand the requirements?

I have just started using TurboCNC and could not make it function well under Win98. From DOS, it runs great. No issues.

It will run in windows, but not very smoothly. Windows interferes with TCNC's ability to output smooth and even pulses.

Boot up TurboCNC in Dos and there are some sample files you can test included. Youll have to calibrate your machine by going through the config menu and configuring each axis with essentially a couple of constants that will define your scaleing. It is pretty simple, you will be able to figure it out. There is not a standard file for the hobbycnc board, but configuring your axis will take care of that. If you have limits you will have to define them as well. Your best bet is at the TurboCNC user group at Yahoo for specific questions. TurboCNC will apear to be operating in windows, but it will have bugs and glitches that will make it unreliable and unpredictable. The only way it will run correctly is in straight pure dos. Good luck, your almost there!

   Thanks for all the responses! I would have tried to get TCNC working in Windows so that I could use the built in networking to transfer files. I will look into DOS networking instead. You guys saved me much time and headaches, I'm sure... thanks again.

   I was traveling for work last week so I didn't get much done. I did find out that the McMaster Will-Call window is only for business clients :( which is too bad because I was in Atlanta. Oh well....
   When I got back in town, I tackled my coupler issue. Since I had some 3/4" aluminum round stock scrap, I decided to give it another try. I basically followed WC1's instructions... but made a few changes.
   Before begining this project, I took a night time maching class at a local technical college. In that course, the only way that I learned to hold round stock perpendicular to the vise holding it was with a V-block. I don't have a V-Block, so I came up with a solution that not only held the round stock perpendicular, but it also made up for any in-accuracies with the drill press.
   I put a small piece of 2x4 in the vise and then set the drill press table so that I could put a 1/2" bit in the drill without adjusting the table. I chucked up a 3/4" forstner bit and drilled a hole in the 2x4 that was the depth of my blank (1.5"). I dropped the blank in the hole and used a hand clamp to apply pressure to the short sides of the 2x4. This method allowed me to not only get the 1/4" and 1/2" holes lined up but it also was the easiest way to find the true center of the blank.
   Once I finished drilling the holes, I turned the blanks on their side and eye balled a location for the set screw. I used #8-32 set screws. To test the couplers, I put a piece of threaded rod in one end of my coupler and then used a 1/4" steel dowel connected to a hand drill in the other end. I tried to run the threaded rod through my Anti-Backlash nuts and failed. The set screw on the 1/4" side wouldn't hold the dowel. I think I might have to grind a flat spot on the dowel... but I don't want to do the same on my steppers, so I'm kinda stuck.

   I took Randyf1965's advice and froze the Anti-Backlash nuts and then re-tapped them. This allowed me to thread the rods through the nuts and get them lined up on the machine. I was able to turn the rods with the coupler by hand but couldn't use the drill. The X & Y nuts are currently assembled in the freezer. I will run the tap through them one more time to see if that will allow the rod to turn with a little less resistance. Hopefully, this will eliminate the need to grind flats on my steppers.

   I went to two different auto-parts stores looking for the reinforced fuel hose with no success. They both had kits with the hose but nothing by the foot. Can anyone tell me where to find the reinforced fuel hose by the foot?

Success! Last night, I pulled the fully assembled ABNs out of the freezer and ran my homemade tap through them twice. The ABNs now fit on my threaded rod very well and can be moved as easily as the 1/2-10 nuts I bought. I completely assembled my X and Y axises and was able to use a drill to move both without having to grind a flat spot on the dowel. The Z axis ABN is in the freezer now. I finally feel like the end is in sight! I hope to have some more pics soon. Thanks again for all the help along the way.

Just a quick update to note my progress. Currently I am adjusting the machine. I have been able to get motion in all three directions but the Y axis binds a bit and the Z axis wobbles on the way up. Unfortunately, I blew 2 driver chips in the process so I'll have to wait for the weekend to make any more progress.

Does anyone have a suggestion for a finish? Since I used hardwood, I'd really like to stain and varnish it. I noticed that many seem to paint. Is there a specific reason for that choice?

"Does anyone have a suggestion for a finish? Since I used hardwood, I'd really like to stain and varnish it. I noticed that many seem to paint. Is there a specific reason for that choice?"

But as a hardwood furniture and cabinet maker.... I gotta tell ya... :(

A lot of the DIY mills are made from MDF. It is a compressed composite of fibers and resins under extreme pressure, somewhere in 50,000 lbs. range. Therefore you get extremely high tolerances. However, you also get a tendency toward swelling if the MDF is not sealed properly.

To seal it you need to put Shellac on ALL surfaces, at least two coats on the flats and four or more on the edges. Some people put a slightly thinned mixture of yellow/white glue on the edges first. The edges are where the moisture in the air will penetrate first. After that, follow up with block sanding between coats of Shellac using 220 grit sandpaper. Follow the Shellac with several very light coats of high quality paint and a clear sealer coat. Shellac is used because it dries quickly, sands easily and makes a great base coat for paint.

Now before everyone thinks I missed Ignatz "hardwood" material useage, chill out… ;)

All I did was set the stage for a comparison of the majority of DIY painted mills and Hardwood.

Hardwood by it's very nature, will ALWAYS absorb moisture into its cellular structure. It is trying to "equalize the to the relative humidity" in its current surroundings. In my area, the Relative Humidity (RH) is about 12%-14%. In my shop it is closer to 8% and in my house 6% to 7%.

As a furniture and cabinet builder, I have to let my hardwood acclimate to its surrounding and the RH before building anything. Why? Because the wood will expand and contract until it equalizes to the RH in its environment. Ever have a painted or otherwise sealed door or window stick at different times of the year? Guess what… its equalizing to the RH…

So, Ignats, to answer your question, you can stain and Shellac your mill but it will never remain constant dimensionally because hardwood has a cellular structure that will ALWAYS absorb or release moisture… it will NEVER be 100% moisture free.

MDF on the other hand, has no cellular structure and if sealed properly and kept away from direct and continuous moisture, will remain exponentially more stable than hardwood. In solid wood furniture, wide boards (like table tops and desk tops and raised panel doors, etc) are attached with additional space at the joints so the wood can expand and contract without exploding in the middle if the night! Conversely, more and more cabinets are being made out of MDF and painted…

Hope I didn't ruin your day or rain on your hardwood… :violin:

If you can keep your mill in as controlled an environment as you possibly can, you will still have movement, but hopefully not as much as in an uncontrolled environment. It is not unusual for some hardwoods to move more than 3/16 of an inch… in a CNC environment where we measure by the .001… 3/16" is like looking at the grand canyon…

Wow, Dave.... Thanks so much for the information. I wish I would've known that before I began. Too late now. In my area(Central Florida), the RH is as close to 100% as it can get until it rains almost everyday. I've had major problems in the past using MDF so I thought that hardwood would be a better choice. Do you think that I could use a Deck Sealer to completely seal the wood? What about a latex paint? Given this situatoin, what's the best choice for a finish to help minimize material movement... or should I just use this machine to cut out MDF pieces for another machine?

... a tough place for humidity.

I looked at your pictures late last night and was unclear if you have used plywood or solid hardwoods or a combination.

As for a deck sealer and latex paint, about all that is good for is mostly, is penetration of standing water. I am sure you have seen the gaps in deckboards change over time. Penetration of standing water will be minimized which will slow the rotting process but moisture will not be eliminated from the equation.

As for painting the wood, latex is more of a surface paint not much of a penetrating material. It cleans and thins with what you want to avoid... water :D
Oil based paints will have more penetration and protection, but will still allow moisture to move through.

You have no doubt seen the moisture vapor barriers (Tyvek Wrap) being put on the outside of new home construction prior to siding... that prevents moisture that will penetrate the siding from penetrating the walls of the home. Reason? to prevent mold and dry rot. It also means that the outer skin of the house, even though painted, stained, etc. is still "breathing" or allowing moist air to travel... which means humidity.

I guess you need to decide on the tolerances you can live with, keep an eye on dimensional changes, possibly make a set of "replacement" panels out of MDF so when the time comes you can disassemble and rebuild easily and not worry about making them "after" the current mill is out of wack.

Depending on your budget, you can, over time, make or acquire critical part replacements out of aluminum or other materials, like Phenolic, etc. It will be more expensive, but in the long run, more stable and predictable.

MDF, when finished correctly, will be reasonably stable for quite a long time. If it weren’t you would not see it going into so many new home's kitchens. The process of finishing these cabinets involves a process similar to powder coating. Heat actually bonds the paint to the surface. In some instances, there is a process where powder coating can actually be applied to wood, but then Aluminum would become cost effective then!

Lastly, as for RH in Florida… it is not so much the % of humidity… it's the change or fluctuation in humidity. If Florida was, say, 96% RH and fluctuated +/_ 2%, that's not such a big change therefore less movement in your wood. But if it changes by 30%, now you have issues. So, pay closer attention to degree of fluctuation in RH not so much actual RH.

If you decide to re-do some replacement parts from MDF for future use (contact me for finishing procedures), I would advise getting the 1" or 1.5" MDF. VERY heavy and more $$ but still pennies compared to Alunminum. I pay less then $20 for a sheet of 3/4" MDF at Home Depot and 1" is closer to $35-40 at specialty cabinet suppliers or sometimes lumber dealers. If you can keep your mill inside some place and control RH fluctuations, you will minimize your problems, not eliminate them, however, it you are relegated to a patio or semi-open structure… not a good thing.

Another choice is MDO. It's the same stuff the states use for road signs, Has a paper coating bonded to thick plywood. Again, finishing and especially edge treatments are critical. More expensive… sometimes easily over $100 for a 4x8 sheet…

All in all, you could get some 80/20 from their Ebay Garage Sale site
(tough to beat some of these prices…)...http://stores.ebay.com/8020-Inc-Garage-Sale_W0QQssPageNameZstrkQ3amefsQ3amesstQQtZkm... and only use the thick MDF or MDO for replaceable tables… then replace them whenever they get bad… save a lot of money and time, and headaches in the long run… after factoring in repeated replacement costs, including cost of running down materials, MDF can become more expensive that extrusion over time… cheaper way to initially learn though…

Dave - Thanks again for the thorough and speedy reply. I'm not using solid hardwood. It looks like several thin layers of wood glued together but I think it was labeled as (Bonewood or Blondewood) Hardwood. I *think* that makes it plywood, right? I can't quantify the RH change daily in this area but it has to be pretty high. I will have to talk to the Boss about moving the machine inside but its currently in my garage. My original goal for this machine was to have inexpensive starting point that would leave me with key components that I could reuse to build a stiffer machine later when/if my abilities demanded it. I've learned a lot from building this machine so far, but it looks like I should just save my money for aluminum and leave this one un-finished.

:mad: I do not mean to imply that you are wasting your time. I would definitely keep going. Anything you learn can and will be applied to your upgraded machine and your learning curve will be used on inexpensive wood.

Once you have it working well, all you have to do is use the wooden structure as a template. Additionally, after you are finished and running for a while (forget about .001 accuracy right now) you will find a number of things you wished you did differently relative to the style and such. Better to find that our in wood rather then Billet Aluminum of Aluminum Sheet Goods.

As far a being in the garage goes, that is not a bad thing. It's much better than a carport or a patio. Plywood will not change nearly as much as solid hardwood. It will have some movement, more than properly sealed MDF, but not nearly as much as a stick of Maple, Oak, etc.

On your edges, where plywood wants to warp, you can use some aluminum channel and a bunch of self tapping screws to hold it in line, similar to a rail and stile constructed raised panel cabinet door. Just make sure you get at least 1/8" material that is at least 3/4" wide so it will be stiff enough to resist the plywood wanting to warp. It isn't all that expensive. And when you get your Aluminum mill built, the channel can be used to mount things to your table, so it won’t be a wasted investment.

By all means, finish the mill, I guarantee you will be glad you did, especially once you start cutting solid Aluminum parts for your upgraded machine. Buy solid Aluminum when you can, cut pieces, mill holes, etc, and set aside for the big tear down and rebuild! Get some Ebay 80/20 extrusion for your table base frame and maybe even your gantry y axis. Mill solid stock for your gantry upright supports and if you want, for your gantry y axis, in place of the 80/20. Mill your bearing supports from Billet Aluminum… Your Z axis mounting plates and router brackets...etc.

Get some 3/4" (16mm) to 1" round rails and bearings from http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=57122&item=7521709535&rd=1 for your repalcement X axis guides (smaller ones are available for your Y axis), heck, I will even give you a set of Thomson rails and supports along with Super Pillow Blocks for your Z axis, but only if you commit to finishing the wooden mill! When you start to make replacement parts for your upgraed, e-mail me... I will set them aside and it can be your incentive to finish and move to the next level.

Then you can start making plates and router brackets to mount to the Z axis I will give you... Here http://www.onlinemetals.com/ is a place that has all kinds of metals at a good price and no quantity is too small...

Do it a piece at a time using your wooden router. Keep an eye on movement of the plywood, but if you brace it and cap the edges, it should be within tolerance long enough for you to jump on making parts for your upgrade. When you are done, you will reuse some of what you had in the wooden mill, so you won't have wasted anything and gained a huge amount of experience. If you stop, you will regret it and might not even finish an Aluminum beauty…

Don't make me have my Marine son pay you a visit…. (chair)

Dave you're the man. Thanks again for the support and the help with my project. Your information has made me decide to complete this router and start on its alum. replacement sooner than I had intended (all assuming I can figure this 3D CAD software out). Cheers! :cheers:

Now for a quick update. The build phase of this machine is complete. I connected the table and support rails usings Larry's Suggestions (http://www.cnczone.com/forums/showthread.php?t=10912). The only difference is that I bought my blind nuts from a local store called Woodcraft (Be careful, this place has lots of toys that are very expensive). I have to fine tune the alignment of the gas pipes and make sure that the ABNs are all adjusted properly. If anyone has any alignment/tuning tips I would welcome the input.

I got the new driver chips from HobbyCNC and replaced the two that had chips missing. All four axises work now and I can control the motion of the machine from within TCNC. I still need to fine tune the TCNC settings for the motors. Currently the machine is jogging at 10IPM. Does anyone have any suggestions for the following settings; Pulse Width, Accel, Start vel, Max vel, Slow jog, Fast jog? I don't really understand what the TCNC manual has to say for these options.


Here's a photo that shows the current state of things.

Ignatz,
Basically, I would set up "reasonable" Low values. When I set up my machine, I tried to get real high rapids, but found that my start values were to high and was actually "snappng" small end mills as the head would move very rapidly initally and have to "slow down" for the cutting speed. I would have start values no more than my slowest cutting speed.
After that, select a top end values and try it. If your start missing steps, slow it down. Same goes for acceleration. Set a slow value and then start increasing it until you have problems and then back it off.
It is hard to give absolute values as each machine is different. Also, once you have done it and then later on find it is not suitable, don't be afraid to change it.
In my case, my base values are as follows (akk values imperial):
Default_Feed=10
Acceleration=16000
StartSpeed=334
MaxSpeed=15000
Fast_Jog=5000
Slow_Jog=175

Hope this helps, but also realize my system uses servos and YMMV

Hi Bubba,

Thanks very much for the feedback. I played around with your values and they were too high for me. I did find the following information in the TurboCNC user group that helped quite a bit.


I wrote a fair number of posts covering setup. You should be able to
find them around the same time frame that AccelErr.cnc in
http://groups.yahoo.com/group/turbocnc/files/GCODE/REL4/ was posted.

Basicly set Start Vel to an obnoxiously high value (1000 IPM), Accel
to a low value (400 or less) and Max Vel to the same as the Start
Vel. The high values are to override the limits so that you are not
constantly working in the configuration menu.

Write a short program to move the axes at controlled speeds, return
speed should be about 1/3 of the test speed. Measure error on
return. Preload the axis in the return direction first to avoid
backlash from interfering with your measurements.

Sample program:

N100 #1000 = 1 ; 1 IPM default Feed Rate

N200 ASK #1000 ; Test Feed Rate?
N210 G01 X1 F#1000 ; Move at test Feed Rate
N220 G01 X0 F[#1000/3] ; Return at 1/3 test Feed
N230 M97 o200 ; goto line 200

Once you've found the Start Vel where you don't lose steps, set this
value in the axis configuration. Now you can use the same program to
determine the Max Vel. Ensure that you can accelerate to your chosen
test feed rates in less than 1/2 the distance that is specified in
the program. Remember that you need room both to accelerate to, and
decelerate from the test speed, as well as travel at the test speed.

Tony
TurboCNC Development Team


Using this method, I found that my top speed was near 27 IPM on my X axis. I haven't ran the test on the Y and Z axis but this speed seems to work well on my machine.

Quick Update - It's Alive! (Almost) :D The machine moves in all three directions and now has the Rotozip mounted. The Rotozip is not square to the table so I might re-make the mount but I want to cut something (anything) first. I have to find a way to transfer files to the CNC machine... either network or USB.

I also need to figure out how to hold work pieces to the table. The JGRO plans call for aluminum hold down tracks. My problem with this solution is that I am concerned that I need to cut the slots with the machine itself so I can be sure that they are square... but I need to test the machine to make sure it is running properly so I'm hitting a Catch-22. Can anymore recommend a solution to this dilema?

Here are some pictures of my first attempt at cutting with my machine. I am using a cheap HF bit and Steve Mazner's 12 Inch Ruler GCode. I think it turned out OK but I still need to address the clamping and tool height issues.

Look great. How did you attach the ABN to the carriages? I'm building a machine myself, and I have no idea to avoid flexing.

js530 - Thanks very much! I'm not sure I completely understand your question, but I think this picture shows how I connected my ABNs to the carriage. The image shows the X axis on the left hand side and the Y axis on the right. I didn't have many problems with leadscrew alignment on the Y and Z axises but the X was another story.
My X axis leadscrew is slightly bent and wobbles when it is spun. The wobble causes whipping. To deal with this I did two things, 1. I switched from the aluminum couplers that I made to LoveJoy couplers. 2. I changed the Anti-Whip block slightly. Instead of cutting two .281 holes in the Anti-Whip block, I drilled three slightly overlapping .281 holes to make a slot. Now, when the screw turns, the Anti-Whip block moves from side to side slightly instead of causing the gantry to whip. I hope that helps.

Hi, Seems to work, that's always a great moment.

How does it hold up? Any updates?
What steppers are you using on it?

Can't wait to make a fixed gantry router like the JGRO design. The moving table does not suit itself well to 4-axis milling... I think you did a good thing to use an existing design... what a headache I had some nights...

Para