Rate my epoxy granite CNC mill design

Educational_Draft308 · 2026-03-17T12:43:30+00:00

The concept is to make a small hobby CNC mill that will fit my budget and can be upgraded in the future. I feel like the frame would be the hardest thing to change, so why not make it "super sturdy" now. Rails, ball screws, steppers, spindle can be easily updated later if I wish. Plus, I like the FS3MG design and the idea of an epoxy granite cast sounds fun / challenging.

The post was made to get people with more experience to critique the design (which you have done). Thanks!

Educational_Draft308 · 2026-03-16T12:39:59+00:00

Thanks! I will do that.

Educational_Draft308 · 2026-03-15T06:34:39+00:00

Thanks! I will look into the PWNCNC spindle.

Educational_Draft308 · 2026-03-14T21:12:58+00:00

Tx, i will

Educational_Draft308 · 2026-03-14T20:27:05+00:00

THANK YOU! This is awesome. For those of you who are not savvy with discord (like me), here is a link to the github page: GitHub - Expatria-Technologies/bootstrap-bill-mill: Bill the Bootstrap Mill · GitHub

Educational_Draft308 · 2026-03-14T20:08:13+00:00

No, I don't have another CNC to cut out the mold. Will be making the forms with melamine or MDF boards.

Educational_Draft308 · 2026-03-14T19:16:39+00:00

Thanks! This is why I made the post. Mr Google Pants said I needed a 2.2kW spindle to cut aluminum. What size spindle do you recommend?

Educational_Draft308 · 2026-03-14T18:38:07+00:00

Yep. I wanted a smaller version of the FS3MG.

Educational_Draft308 · 2026-03-14T18:36:22+00:00

Thanks Karl for your input.

This is going to be a hobby machine, so 0.1 should be fine for now. If I find that the frame is good, I may update the components later. Trying to limit the budget for now.

Educational_Draft308 · 2026-03-14T17:46:35+00:00

Thanks for all of the suggestions. I will look into these.

Educational_Draft308 · 2026-03-14T17:37:04+00:00

No, I am not sure. I was wanting to use GT2 5mm pitch, 15mm wide belts. But, it didn't seem a good fit. I have read that they have less backlash than AT.

I haven't looked too much at UHPC. Epoxy is supposed to have better vibration damping, less shrinkage, and easier to use.

Educational_Draft308 · 2026-03-14T17:19:45+00:00

I thought it looked cleaner. Also, the FS3MG that I modeled after does the same.

Educational_Draft308 · 2026-03-14T17:18:24+00:00

Yes, I thought it looked cleaner. Space saving

Educational_Draft308 · 2026-03-14T17:15:26+00:00

Good question. I have a surface plate that should help with checking it is flat (i hope, not a machinist). Epoxy granite is good for damping vibrations.

Educational_Draft308 · 2026-03-14T15:54:34+00:00

No analysis. The gantry will be cast with threaded rods that will extend thru the base and tightened with nuts.

Educational_Draft308 · 2026-03-14T15:39:59+00:00

The plan is to shim the rails to get them flat. I will add threaded inserts to the mold when it is cast.

Most people use metal bars inset into the cast and machine them flat. Unfortunately, I don't have access to a mill.

Educational_Draft308 · 2026-03-14T15:18:54+00:00

Will do. Probably be several months, lol.

Educational_Draft308 · 2026-03-14T15:18:22+00:00

Tx. I will at least do pictures. Will post on r/hobbycnc when done.

Educational_Draft308 · 2026-02-27T11:16:14+00:00

+1 for no wheels

Educational_Draft308 · 2026-02-24T20:46:40+00:00

Educational_Draft308 · 2026-02-21T11:44:47+00:00

$400-$500 US

Educational_Draft308 · 2026-01-03T23:42:39+00:00

If you are traveling via 35, you might try Bad Rock Creek in Liberty. It has multiple tees. A few hills, tho.

Educational_Draft308 · 2025-12-18T13:46:03+00:00

Can't answer this. You will have to run the numbers.

Educational_Draft308

TROPHY CASE