Clamping // Spoilboard

Is this ok on mdf? Only asking as that was exactly as what I was intending to do, just looking for confirmation :crazy_face:

I used MDF for my spoilboard. Just take a really really light cut. I started with a really slow feed rate and bumped it up suing the controller while it was cutting. I think my DOC was 1mm and I made two passes to fully level the board.

Ummm
 I’d avoid surfacing MDF if you can avoid it. Aside from the dust being Australia-level aggro lethal, the factory surface is already pretty dead flat unless you’ve gotten it wet. Either work on fully squaring your rig (including tramming your spindle), or figure out Marlin’s mesh bed level functionality, and let it take your lack of flat into account.

Alternately, if you’re not terribly far out of flat, and the projects you’re doing don’t require monster precision, don’t worry about it. Mum and Dad won’t notice that the Home Sweet Home sign isn’t dead-on accurate, Cousin Jim won’t care if the relief-carved Vader mask is just slightly skewed, and the Spinster McGill won’t see that the eyes on the many playful cats are different sizes, they’ll all love the neat gifts/art they’ve gotten/purchased.

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I thought as much, I have a dial indicator on its way, everything is level in relation to each other X and Y rails etc

Do tell.

My 49x49 spoilboard is MDF. I shaved it down 1mm with the Whiteside bit over the weekend, and am pleased with the results. I feel the amount of dust people forewarned was exaggerated.

The important thing isn’t flat, it’s parallel to the travel of the bit. If the gantry dips 2mm in the middle (consistently) then your surfacing bit will too. Then when you mill, your material can flex the 2mm over the whole length.

Also, anyone who has tried to level a 3D printer bed that is only 8"x8" knows how hard it is to get something that big actually flat.

There are a lot of projects where it just really doesn’t matter. There are tricks to make it matter less (finer bits, re zeroing for local carves). But if it does matter, surfacing the spoil board is a cheap and easy way to do it.

MDF has a big advantage after you surface it. The small particles it’s made out of means the resulting surface can still be smooth. Plywood, in contrast, can pull up big splinters and leave the surface uneven. The other problems with mdf are that it will swell when you drive a screw into it and it is harder than many woods, so it can need slower settings.

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