Jacob R.'s CNC Router
When I started this website, I though maybe I would get a few building this machine, and to the tee. My intention was to make it so that they can provide their own alterations and sizes. With Jacob's machine, the intent lives up to it's promise. I think, if we take all of the great enhancements from all of the builders you see on the list, we would have an even better machine. Jacob did similar enhancements to the bed of the machine, reinforcing it so it would not sag, but he did not stop there. This guy is a true modder. He salvaged a component from his router to serve as a clamp. He also enhanced the lead screw nut adapting a flange to secure to the transfer piece. He has also selflessly provided an AutoCAD file
to share with this community (with double rail x-axis modification).
I will let him take over: Thanks for taking the time to put of this information into a nice step-by-step how to!!! It has really helped a lot.
I have made, or am making, my first cnc machine. It took me about 2 weeks to get up to the point I'm at now. I took your basic design and added a couple little things to it. I found that drawing it up first helped me figure out exactly what I would need. Attached are some drawings I made in AutoCAD and some pictures of the "somewhat" finished cnc router. Feel free to do with them as you please.
I added a torsion box like Mike H. did, but instead of using little individual pieces, I used long runners with slots cut into them to interlock them together. I screwed the bottom sheet to them, no glue. I was also going to use two rows of X axis rails to help with the weight support, but found that was just a little over kill and decided to leave the bottom one out. For the router mount, I used an old chop block that I had laying around. It's made out of 1" thick high-density polyethylene (aka strong plastic). I bought a Hitachi router from Lowes and it came with a plunge-base. I used the quick latch off of the plunge-base as the latch for my router mount. It works pretty good, letting you take the router off if you need to use it quickly. For the axis nuts, I used binding nuts I got at McMaster-Carr(search: binding nuts). They work pretty well sitting on the outside of the mdf and they don't split the mdf (even though I did manage to split one piece, but that's a different story). I also upgraded to 5/16-18 all thread rod, mainly because Home Depot was out of 1/4". I just ordered the motor kit from hobbycnc.com, so I should be done in about a week and a half.
Thanks again for all your hard work to make it easier for someone to make a CNC Router!
Back to Patrick: We can all learn from the resourcefulness of Jacob and the modifications he provided. I am really impressed with the latch idea. It's almost tempting to buy the router just to acquire that latch type. The latch on my router base isn't so easily adapted. I also notice that the router mount is similar to the router mount on my previous machine. It's the squeeze method of holding the router and it will work well with HDPE (high density polyethylene).
The lead screw nut also make good sense and will probably last a bit longer than my technique. This nut assembly that exists on this machine requires two smaller wood screws driven into the end of the MDF. To stiffen it up and prevent any possible splitting, some glue might do the trick (epoxy).
In this image you can see the nut from McMaster Carr to drive the y-axis assembly.. That's slick. You can also get nuts with flanges for ACME lead screws at various distributer, although it's a little (lot) more pricy. Roton has them for a relatively good price, but the shipping is a killer.
Here is the same nut flange type on the x-axis assembly. One possible recommendation I would make is to put this flange on the bottom of the assembly. The pulling force caused by the weight of the router and the z-axis mechanism may put too much stress on the two screws holding the flange on the wood. If the flange was repositioned to the bottom of the z-axis back support, the two screws would only need to keep the flange in position, and very little force would act on the flange. In fact, the force would only be shear (a force applied laterally).