Extrusion Bed Upgrade

Looks like I’m about 3 years late to when SO3 extrusion beds were in vogue, but decided to address the flatness issue once and for all. You know, rather than simply rotating my MDF strips and re-surfacing. Scope creep, what’s that??

The PwnCNC kit was the easiest way forward, and I didn’t love sourcing my own (wider but thinner) extrusions from other sources. It’s also great to still work with 1/4-20 hardware so I have minimal retooling on my clamping and locating solutions. The current T-Track below MDF worked great, even losing some Z height. The hardest part about this is I have to rework the CNC while it’s inside my custom enclosure, and I can only move the enclosure table forward and backward about a foot (room was built AROUND the SO3).

Extrusions went together very quickly, and I would suggest the extrusion plugs are REQUIRED not optional. They make a world of difference for aligning each piece of aluminum, centering between the metal frames, and making the whole bed act more like a single unit. It will bow in the middle until you set it on the steel, which is expected. I printed my extrusion plugs from PA-CF for extra piece of mind.

Saw the Z-Plus units are being discontinued this fall, so decided to jump on that as well. I’m not sure when I’ll work up the motivation to do the install since it’s pretty intensive with updating all of the limit switches as well. But a worthwhile upgrade as I’ve been pushing my machine harder in the past few months.

Love the look, going to add a 1/4" MDF spoilboard strips on top with access to the extrusion track below for 1/4-20 clamping. Let me know if there are questions or feedback!


Looks Nice. My SO3 XXL just has an MDF spoilboard with 1/4-20 Tee Nuts. I made a torsion box for my SO3 to sit on with a piece of 3/4" rigid foam underneath the SO3. The center of my XXL sagged and my first fix was a piece of plywood under the center rib. After I put the torsion box on and took my leveling feet off the SO3 sits flat on the foam and has been very good about keeping the bed from sagging.

Where did you get the alum extrusions?

Since my spoilboard is mdf and tee nuts I use a combination of cam clamps and the green basic hold downs from C3D. I have the Tiger and Gator clamps but seldom use them. Usually the only time I use the hold down type clamps is on plywood. The edges tend to curl up even with the super glue and painters tape.

My SO3 has been a great machine. I also have the HDZ and the BitSetter and BitZero. The BitSetter and BitZero make using my Shapeoko so much better.

Keep on machining!

It’s a drop ship kit from 80/20 but sourced through PwnCNC here -Extrusions Bed Upgrade Kit for Shapeoko 3 – PwnCNC. I really wanted something that went together quickly and didn’t require too much fiddling inside the enclosure, but a torsion box is a sound engineering decision as well. I love the Tiger clamps, they are my go to when not using double sided adhesive. Haven’t needed to do tape+superglue for a long time.

The flexibility of the Shapeoko XXL is one of the things I love about it. I also upgraded w/ BitSetter and BitZero when those came out a few years ago. Massive QoL improvements, and the new Carbide Motion makes that workflow really sing.

One more “before” pic showing the SO3 pulled forward so it’s hanging out of the enclosure. You can also spy the baby brother Pro XL on the bottom deck!

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Are you gaining Z room with that extrusion? Are you using any kind of spoilboard on top of it?

Not from stock, the extrusion is a few mm taller than the cross straps + original MDF bed. I will be putting 1/4" MDF as a spoilboard on top. This is still 1/2" shorter than my previous setup though.