Any tips for cutting birch plywood?

<!–more–>I’m going to cut some 1/8” birch plywood and was wondering if anyone had any tips on what settings and but I should use?

Diameter of your bit, what kind of bit, and what are the usable dimensions of your build?

 

If that sounds boring to you, start at 8mm/s feedrate, 4mm DOC, 3mm/s plunge with a 45% stepover. Use peel of pockets.

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If it’s low quality, a downcut bit will really help keep the top veneer from pulling off, but you need to be careful not to plunge too far. The bottom will still be a little fuzzy, but not as bad because its against the spoil board.

In my experience, BB ply mills great, like sugar cookie dough.

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I had good results cutting a few shapes out of 1/4" plywood using a 1/8" end mill, but I’ve lost track of the other settings I used. They were probably very close to those suggested in the basics guide since they were the first things I did. I might have gone a bit faster than suggested, but not much.

Cutting slowly (as suggested by Ryan) seems like a good idea in plywood that thin. The faster the machine is going when the cut finishes, the more likely it is going to move the finished part and maybe nick a tiny bit out which happened to me.

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1/8” single flute and 2’x2’.

Okay here’s what I got with an 8mm feedrate. It looks great, but some of the pieces that were thin were knicked off. Was this due to me not having a solid piece of plywood under the birch, the wrong bit, or is the feedrate too fast?

[attachment file=55252]

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That does look great. It looks like it broke along the grain. There’s not much you can do except repair it. It’s just a consequence of a natural material, being pushed to the side, along a natural fracture line.

You might get less force on it with a sharper bit. Or maybe a smaller bit.

You can try to leave those parts thicker.

You can use thicker material.

You can use a laser instead of a router.

Or leave a few more holding tabs.

Looks great though!

Hmm, I actually did t even use tabs, that’s a good idea though. Here’s what I was using under the birch. Does it need to be a solid sheet of wood instead of the few slats that I used?

[attachment file=55317]

Hmm, I actually did t even use tabs, that’s a good idea though. Here’s what I was using under the birch. Does it need to be a solid sheet of wood instead of the few slats that I used?

A few tabs and a solid base will help for sure.

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If you used double sided tape with a solid backer–and then really press it down hard before starting–maybe it would be enough to secure the rickety parts of the carving from flying off into space. I use GG-200 tape, which has a strong grip, but you can still remove it afterward without much trouble (http://a.co/8xdfu27)

 

Also, if you have runout on your spindle/bit, it might be a contributing factor. Maybe worth checking for that also.

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Are your t-tracks and spoil board the same thickness? I have 5/8 tracks with 3/4 melamine spoil board, with 1/8 clearance o don’t have to worry about cutting track and replacement spoil board is basic shelving material.