2 inch grid my first project XXL3

My first project, 2 inch grid using waste boards that came with my Shapeoko XXL3. 1/4 20 inserts from underneath. Worked out nice. Thank you for your support Carbide3D.


Can you post a photo of the inserts? I like the idea that you installed them from the bottom (Now why didn’t I think of that)

Mine are from the bottom also. You can resurface your board may times and not even get close to them. Works great!


I got them though MacMaster-Carr part # https://www.mcmaster.com/#92105A100

I used a .316 dia hole to make them tighter.

Hope this helps.

Thank you.


I err, meant a picture of the inserts IN the board. Haha, my fault for not being clearer.

I have used these with some success, albeit I also used their special tool and I only installed half a dozen inserts (also from the bottom) to secure a smaller threaded HDPE cutting board. Has anyone used both and know of the pros/cons of either? I have 50 or so left and I’m looking to replace my stock XXL MDF spoil board, but before I do I’m wondering if there’s better insert options? Thanks, Dan

The T-nuts require that one countersink the bottom of the wasteboard which is a pain and makes for a more complicated file. Easily installed w/ a ratchet and a good quality bolt and a couple of washers (working up to a fairly large one to distribute the forces)

The threaded inserts create the possibility that the board will bubble up on the top or bottom and distort due to the pressures of the thread interacting with the material. Not needing to drill a countersink means it doesn’t matter whether machining is done from the top or the bottom.

One other option would be to use a material which would allow directly tapping for threads.

With the correct drill bit for the fastener and the proper installation tool (there’s a kit with tool, bit, and a half dozen inserts) I haven’t seen the bulging problem too much, but I have before using a drill bit that was “close” and a flat bladed screwdriver instead of the “tool”. But again I only did a few, so I can’t say these problems wouldn’t crop up in time. The others, as mentioned in earlier posts do look like they would work a little better, but then there’s the counter bore which if going from the bottom of a stock wasteboard and trying to CNC the holes could be a problem. I think I like plan C, use a material that can be directly tapped. I have a 18"x24" HDPE cutting board that I’ve threaded and works “OK”, but I’ve been looking at just replacing the whole XXL top with one piece of 1" Starboard, but it’s expensive at that size :frowning2: That’s why I’m more curious about just making MDF “work”. The project the OP did looks pretty good!

I have some time to think about it though as I’ve recently purchased a new house and it pretty much eats up any “fun” garage time. I’ve just finished redoing the paint in the garage, waiting on an electrician to set up a dedicated garage circuit, bought an air hose kit for my compressor, started setting up work benches, and bought a mini lathe from Littlemachineshop.com. Oh yea, and I’ve been helping my wife pick out paint colors, …meh… :frowning:

Thanks for the input!



What I did was to take the back board and flip it over on top of the front board with a piece of cardboard in between, attaching them with longer screws, and clamps. Then I ran the program I created, for both the .316 dia though holes and the .496 dia recess at .030 deep. Once the first half was done I flipped everything, aligned it all back up and ran the program on the other half.
Then once completed, I installed all the inserts from the bottom side, insuring they were all just below flush. Then reinstalled them both.

I hope this helps.



I’m impressed, thanks.

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