Yet Another 8020 CNC Build

[jsantos]

Originally Posted by longboarder Im thinking about building a machine like yours. Do you have any plans or do I need to go by the forum here? Thanks Ron

Hi Ron,

Sorry, I only saw this post today. And sorry, I don't have any plans other than what I have on this build log.

Good luck on your build.

[jsantos]

Originally Posted by grakan I hope to get time to build something similar within a not too distant future. /Grakan

Good luck. Do a log so we can all follow your build. :-)

[jsantos]

Originally Posted by the4thseal the kapex makes you statement that you have not bought a festool in the last couple of years funny. i have not bought anything in a while but i have stacks and stacks of white boxes. there is new stuff coming that has me frightened...i have seen and used some of their prototype stuff that is in the shoot.

So what new stuff do they have coming? :-)

[svanommen]

jsantos,

I just wanted to let you know this build log was the deciding factor for me to finally build a CNC router of my own. I feel that I owe you many beers It's taken me way too long but I am almost finished.

Thank you for taking the time to post such a detailed and helpful build log! I can only hope that my machine comes close to what you have done with yours.

Feel free to comment / critique my build here

Cheers,
Seth

[watsonstudios]

Can you post a link to the model of this Gecko enclosure? Mouser has soooo many enclosures, I'm not sure where to look or the exact size of the one you're using. The enclosure you have is perfect. I'm using a 540 also and probably the same power supply from CNCRouterparts. Thanks,
Jon

[jsantos]

Originally Posted by watsonstudios Can you post a link to the model of this Gecko enclosure? Mouser has soooo many enclosures, I'm not sure where to look or the exact size of the one you're using. The enclosure you have is perfect. I'm using a 540 also and probably the same power supply from CNCRouterparts. Thanks, Jon

Not sure what you're referring to as I've changed enclosure twice already.

The smaller one I used is Hammond 1402KV. I switched to a bigger one in preparation for adding another controller and it's Hammond RMCS190513

[watsonstudios]

Thanks for the info. Those enclosures are a bit steep for my budget, I may just convert an extra PC case for now.

I saw you mentioned replacing your CRS with linear rails. I am doing the same. I found some 25 size THK rails & blocks for my Y and 1" supported round rail (Thomson) for my X axis. To me, I think that is the weakest link for these CNCRP builds. Me & Ahren spent the last 2 months trying to trouble shoot some accuracy issues with my machine and it came down to the rails & R&P rack. I replaced my Y rack once already because the first rack was not straight enough. I need extreme accuracy because I'm cutting slot car track and the 1/8th inch slots need to line up almost perfectly. Also, these are modular track pieces, meaning all pieces need to be compatible with all pieces so symmetry is also important. After assembling my machine, I ran some tests cutting slots 4" apart in X and in Y. I was getting variations in my spacing, as much as .01 - .02. This was not good enough to cut production track pieces. Ahren also cut the same test on his demo machine and got similar results. I was actually relieved because now I didn't feel like I was crazy!
I actually have the first "hybrid" CNCRP machine. I can switch between screw drive and R&P drive on my Y axis. I installed the screw drive option to rule out any R&P issues. So far the screw drive is a bit better but I will run more tests once I install the new Y rails. (rendering & photos attached)
Anyway, Ahren has great parts and I would still recommend them to anyone. Fortunately the parts that have been less than precise have been the steel rails and 1/2" rack (which are not CNCRP parts). You really need to spend some time, with a dial indicator, tweaking the rack and steel rails making sure they are mounted straight & parallel. I made a little rig that I slid across the top & bottom of the 3060 that held the dial indicator so I could torque each bolt for the best alignment. I even removed my rail clamps because they were not even needed. After that time spent, I was able to get pretty good numbers on my last test, with the slots being off only by .003 at the most and that's pretty good (using the screw drive setup).

I also attached a rendering of the round rail conversion, still using Ahrens R&P system. Unfortunately I may need to retire the risers but I'm still working out the design. My smaller router had the 1" round rails and they were damn straight! So, I'd be curious on how you're going to incorporate your linear rail conversion. What did you find for your linear rails?
Jon

[jsantos]

Hey Watson,

I was able to get the THK HSR35 rails. It took me six months to collect them, but I was able to get them all from ebay. But I haven't installed them yet. I haven't had accuracy problems with my CNC and it's been working very well for me that I haven't really had a lot of incentive to install the rails.

I'm thinking of installing the rails underneath the 8020s so dust won't become a problem. I currently have the 3030 but I will probably go with a 3060 to deal with possible sagging.

What screw drive did you use for your y-axis and how did you mount it?

[watsonstudios]

35's are a good size for the X axis for sure. My Y rails are THK SHS25's Got 2 74" rails and 4 blocks for 300.00 - killer deal!

The screw drive system is just the standard parts from CNCRP, the same parts used on the Z axis. A couple bearing blocks, 1/2" shaft collars, a few sets of thrust bearings, a motor mount, coupler, and new aluminum cased lead nut - all for the 1/2" 5 start ACME screw. You can see in the attached pics, I just cut a couple of 2" pieces of 1530 and bolted them to the ends of my 3060 to mount the screw drive parts. The nut just bolted right into the high Z plate right where it needs to be. All I have to do, to return back to R&P mode, is take the screw out and mount the Y motor back on the R&P pivot arm. Takes 5 minutes.

For my X rails, I will have to replace my 1530's with 3030's to mount the rail supports, which happen to have holes exactly 1.5" apart which is perfect. I already have the long pillow blocks, which also have holes right inline with mounting to the 3060 riser. 1" round Thomson rails are perfect for 8020 builds. Picked up 2 111" supported rails off ebay for 300.00 as well, again, pretty good deal.

I'm also still planning on building a better table. Probably have a local shop weld up a steel table, It would be cheaper than building it from 8020.

[Drools]

I'm not sure if you have decided how you are going to mount the THK rails to the 8020. In my build which used CNCRP parts, 8020 and THK HSR25 rails (very close to the SHS25s) I used .25” bolts, since the rail mount holes on are .2756” this leaves a little bit of wiggle room. The main reason I went this route was so that I could use the nuts that 8020 make which are self aligning to a degree. The SAE hardware is easier to find and less expensive that the Metric parts.
To help with the alignment I make blocks out of Baltic birch which bolted to the 8020 then I clamped the rails to the blocks.
Make sure the blocks you are using have dust seals installed, this prevents the blocks from rolling-over any dust on the rails. Since my machine is much smaller (38”x48”) than yours I went with screws instead of the R&P system from Ahren.
I included pictures of the hardware I used.

[vtx1029]

I'll be interested in your upgrades. I'm thinking of going to thomson rails as well. The CRS I got was not in the best shape and rather then spend another 100 or so in CRS for 500 I can get the thomsons and be done with it.

Hey Joe,

Look at the 1545 extrusion for your X rails. Its pretty darn strong.

[watsonstudios]

@drools, I'm going with the recommended 6mm cap screws and 6mm 8020 t nuts. I found a great deal on these on Ebay. A guy named tnutz_com sells t nuts real cheap. Picked up 100 6mm tnuts for 35.00 (best offer) and 270 6mm x 20mm cap screws for 15.00. Hell of a lot cheaper than buying from Ace Hardware!

@vtx1029, I'm going to switch to 3030 for the X extrusion since the rail supports already have mounting holes spaced at 1.5" (across) and bolt perfectly to the top of the 8020. 5/16 18 bolts will fit without drilling out the holes as well.