My solution for a rock solid, non-flexing, XXL base

CNC Machines Shapeoko
1

I have been relocating my XXL into my new shop I recently had built and thought I would share my improvements for making a much more stable and rigid platform for it. One of my upgrades was an aluminum bed, but even with that there was still more flex in the unsupported center of bed than I liked.

So my first change was to replace the 4 feet with a system of nuts and bolts that secure it in all 4 corners to the base. In addition to keeping the machine from sliding around, the combination of opposing nuts I used allows me to level the machine with great precision. Also because the cnc is held firmly, I can push up on the bed from the bottom in various places to fully support it (covered below).

This hardware stack is (from top to bottom): [bolt, washer], cnc frame, [washer, lock washer, nut], [nut, lock washer, fender washer], plywood base, [fender washer, lock washer, nut].

Next I added supports for the middle of the end plates. Even with the beefy angle iron, and an aluminum bed, there was flex happening here. So I added threaded inserts into the plywood base, then from the bottom screwed in a bolt, which is capped off from the top with an aluminum spacer (and blue thread locker). I lock the bolt in place from the bottom with a lock washer and nut, again, creating a fully tunable system.

This hardware stack is (from bottom to top): [bolt starts, nut, lock washer, fender washer], [plywood base, threaded insert], [bolt end, aluminum spacer]

Then I added the same supports for the cross straps that connect the two end plates. There is one per strap. The additional two on the right you see was my attempt to fix a shallow bend (0.004") in the aluminum bed. I ended up not using them.

The final product turned out amazing. After all the supports were snugged, the entire thing is extremely rigid. Also, because I am able to tune the height of the supports, I was able to get the bed dead flat using my 36in starrett straight edge. Due to the weight of the bed, it was definitely sagging slightly. And finally, because the cnc is tied into the plywood base, the base is rock solid as well. Its basically a single unit now.

Hope this helps someone else.

12 Likes
2

I’m looking for something similar but need it to be able to withstand the force of an S3 rotating/hanging on folding table. Apart for “sandwiching” and being able to access the underside but I’m not sure there is a good option here.

I don’t trust a threaded insert/t-nut in a folding table application.

3

This looks awesome, I bet it’s rock solid.
Have you considered putting sand or similar in the extrusions as well? That would knock out even more of the vibrations.

Thanks for sharing, I’d like to do similar with mine

3 Likes
4

This is precisely what I want to do with mine. I read where lots of folks use the mat underneath but I feel this is relatively simple and will make for a no flex waste board all over. Nice setup!

2 Likes
5

Why not just mount an MDF sheet underneath the end plates?

1 Like
6

While less elegant than @Croy9000’s solution, I did that and never looked back
image

5 Likes
7

@neilferreri For stability that would totally work, and in practice is fine, if not awesome (especially if you are leveling a spoil board anyway). The method I used just gives a lot more controls over the initial flatness of everything. If you have unevenness in your base surface, then laying MDF support panels on top will just transfer the unevenness up to to the CNC wasteboard. Said another way, I didn’t trust the base I built, so these adjustment feet let me keep the CNC isolated, yet completely supported. Overkill and overthought? Maybe, but its part of the hobby and fun for me.

1 Like
8

@Croy9000 Are you planning on mounting a waste board on top of the AL bed? If so is there a reason why you had all the threaded holes done? I am planning on adding a full al bed as well, but I’m just trying to figure out if I want to pay or take the time to do drill and tap that many holes if I won’t have access to them anyways?

9

It came that way since I bought the Ohio Diesel one. If I had built my own I would have not had that many. But yeah, a spoil board will be added soon.

10

I have the Ohio Diesel XXL and definitely have a lot of flex to deal with. I bought the little twist feet and they work very well but are a pain to slide to the middle from sides. Your system is way better!

Leveling feet

11

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.