Examples of Replacing Angle Iron Supports with 8020 Aluminum Extrusion on Shapeoko 3 XXL?

I am curious if there are any examples of people replacing the angle iron supports underneath the work table of the Shapeoko 3 XXL with some sort of 8020 Aluminum extrusion?

I would like to do this because the provided supports are not stiff enough and bow and bend under force.

I feel adding some much more robust supports would really help it out as well as make a more modular approach.

If not I will be sure to share what I come up with!

Thank you for any tips!


Like that?
Link to actual product upgrade

I made one for the S3 Standard, it is very nice.

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Many people just put a rigid foam underneath which helps with sagging but doesn’t help with resisting lifting due to cutting or clamping forces.

I simply put plywood fillers under the steel straps, drilled through and bolted the whole assembly down to the torsion box it lives on. No more sag, much less vibration.


I was having issues bolting down parts and having the bed flex even with a 1/2" aluminum spoilboard.

Max, I’m curious on what you measured/experienced/noticed for “bed flex”?

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I started with CNC in November 19, I ordered the XXL S3. Upon assembling I noticed the frame only had one thin cross strap in the middle, I ordered a 1/2 metal spoilboard from Ohio Diesel thinking that it would strengthen things up and all was good. Over the next year I had un-explainable depth and edge issues I could not figure out, thinking I was making mistakes or V wheels were off or whatever. What was happening is when I would bolt stock down with clamps, the bolts would pull up on the surrounding area enough to cause measurements to be off. Probably not noticeable to most but I try to gap pieces .0075 etc. to fit together, and was constantly having issues.
When I ordered my SPro’s I was very happy to see regularly spaced frame rails, and since all my models are setup for an aluminumn threaded spoilboard, I designed and special ordered 3/4" boards for my Pros, and the rigidity has eliminated all my wtf moments on gapping parts fitment properly. The S3’s I decided to keep and mod, are both setup with the 80/20 frame with 1/2" threaded aluminum spoilboards, and it has a strong cross section frame and base with lots of attachment bolts, and does not flex like the bent steel S3 frame did when I was tightening clamps on it.

Thanks! Now I know that your spec is well within my tolerance. I don’t do any metal work on my machine.

Thank you for the responses everyone!

After doing my research I do believe I will end up purchasing the SO 4 PRO as it fixes many of these problems I am experiencing.

It looks like after getting the new extrusions, the HDZ Plus, and the aluminum spoil board it will nearly be the same price as a new SO 4 PRO.

I will list my current SO 3 XXL for sale.

I thank you all for chiming in. Some of your builds are gorgeous!!!


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