Threaded inserts.......?

I have the SO3 XXL and just doubled up my waist board and did a 2" O.C grid pattern. I ordered 200 1/4’-20
threaded inserts and drew it up to but 1 at every intersection…that’s 224 !!!
Is this overkill or good insurance? I want to do this one time and hopefully right, the first time. My clamps are about 5" long with 2" slots which is how I came up with the “design”.
What’s your thought and what do you use for a layout? Thanks Ray

There’s a bit here:

I wrote up my thoughts here:

The grid sounds good as does the reasoning between the spacing and clamp size.

I have mine @ 50mm apart. Very happy with it. You really doing it one time a little overkill goes a long way.

Have fun and make sure thread from underneath.


I did decide to go 2" on my grid and the same on my threaded inserts, which gave me like 246 holes to fill lol.
Cutting some clamps now to complete my workspace.

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Nice clamps! Are you cutting them from PMMA? Can you share your cutting parameters? Mill diameter, feedrate, spindle rpm? Tnx.

Thank you.
It is 1/2" polycarbonate from Bayer (yup the aspirin people). I buy 15" x 48" remnants from my metal supplier for $27, includes state tax. Whole thing was milled with 2 flute 1/4" mill bought at Home depot (worked well). Speed was 6 on the dewalt with a feed of 60 IPM, .08 DOC and 41% step over. I didn’t leave any kind of offset for a finish pass, may have improved the finish but I think the bit has more to do with that than anything. It took 27 minutes to cut all 6 of them.
I still have the gcode file for CM if any one is interested or the drawings for that matter, I don’t know how to post either.


Damn that’s a good price. I need a supplier like that :smiley: Well done on the clamps