Recommended wasteboard hole spacing

Hi all,

I was planning to go with Ben Myer’s threaded wasteboard and clamp design. Then I saw the new Carbide 3D corner square and gator tooth clamps, which I have now ordered.

Now I’m trying to figure out the right hole spacing. The corner square has holes 77.5mm apart, but I think that’s going to be too far apart, so I’m thinking 38.75mm apart will allow me to securely hold anything that fits. It’s not entirely clear how far the gator clamps will reach.

Does that sound right, or should I go with 25.83ish mm?

BTW the shop points to a wasteboard design that is spaced 2" apart, I don’t see how that’s going to work with the new square…



I have the Myers Woodshop spoilboard, fences and cam clamps on my XXL. It has worked very well for me but it is a 2 inch spacing. I live in the US where the imperial standard is still in use and have used the inch system all my life. The metric spacing is very logical but because of my lifetime of experience I use the imperial system.

To your point of spacing the 2 inch spacing on the spoil board and the large cam clamps has worked very well for me. If you want to use the metric system go ahead but those “ish” measurements can be problematic. Design your self a spoil board that has the corner clamps measurements in the corner and the 2 inch spacing on the rest of the spoilboard. Choosing metric or imperial does not matter because we have both imperial and metric Tee Nuts and bolts available. So if you are comfortable with the metric system then make your plans and implement.

I have the Myers fences, L brackets, cam clamps both large and small and it has worked well. I have had to shim with small blocks of wood on some projects because not every situation can be foreseen for clamping work. Just try something and see if it works and change if necessary.

I think hole spacing along the longest distance should be less than half the length your longest clamp will reach…


I wonder why…
Maybe the thought is anyone could add holes for it and probably won’t hit any other holes they might have in the wasteboard?
If I were planning on using that square, I’d probably just add extra holes for it. I use a 45mm spacing with alternating M5 threaded inserts and 8mm dowels for alignment. I’m not in love with the spacing, but I do love having the dowels.

Aren’t the clamps just these, modified for a smaller hole?

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Thanks @WillAdams - What’s the reach of the gator clamps? And do you know the logic behind spacing the corner holes at 77.5mm?

I guess that’s the way I should have asked the question. Why is the square spaced at 77.5mm.

Yes I could have the outer ring holes spaced at 77.5mm and all the rest spaced 2" but that just felt weird to me.

77.5mm is a little over 3", so I think it’ll be too far for the gator clamp to reach. Hence 38.75mm, about 1.5", appears to be the right spacing.

Depending on orientation anywhere from 15–45mm — for purposes of leverage it’s best to be on the shorter end of that, so ~25–30mm would be a useful reach distance.

As I’ve noted in the past, if I ever do a threaded insert wasteboard again it’ll be done by drilling all the way through from a master file and installing insets from underneath as needed.


Thanks! that makes sense, I’ll go with 25.883 (77.5 / 3) so I’m in that range and the square fits.

Actually that’s an insane number of holes, 450 odd! I’m going to go with 37.75mm, just 231 holes :slight_smile:

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And that is why I’m never planning on doing a specific grid again — if I ever do threaded inserts it will be on an as-needed/where-needed basis from a master file — I’ll drill through, use a drill and a template to finish from underneath, then install the threaded insert from the bottom.

Similarly, when I replace a spoilboard, I won’t add holes in it until necessary.


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