Problems cutting 1/8" Paduk

[rcnewcomb]

I have some 6"x12" pieces of 1/8" paduk (hardwood) that I'm trying to cut but the wood cracks badly during the final cutout - long cracks along the grain of the wood.

I'm using a 1/8" bit and I'm holding the material via screws at the corners.

Would a vacuum hold-down lessen the cracking problem or do I just need to take very gentle, multiple passes with thin hardwoods?

[Brady Watson]

Randall,
Vacuum would probably help with the hold-down because you would be eliminating some of the vibration and much of the stress on the grain from the screw acting like a wedge when the force of the cutting tool moves against the grain.

You may find that the best approach is to do multiple passes on the parts. You'll have to experiement with the depth...start at .04 deep.

If I were cutting it, I would create 2 toolpaths. Let's say the material was .125" thick. I would add .03" Allowance to the toolpath and only cut it .100" deep. I would do 2 passes at .05" per pass. This would leave you .025" of material allowance left on the entire profile of the part AND a .025" skin at the bottom. I would then create a 2nd toolpath than went the full .125" deep with NO allowance. This will give you a nice clean cut with no tear-out and it will clean up the waterline marks that the multi-step pass created.

Hope that helps...I know it seems a bit complicated, but sometimes that is the fastest way to get a nice clean part when the material is challenging to work with.

-Brady

[les_linton]

Randall,

I have been cutting a lot of exotics, bubinga, cocobola, zebra, leopard and have found that leaving a skin of .020 and running the whole piece through my drum sander works well for me.

I use SplitStop screws, but still pre-drill for hold down.

Brady's way works well also, but I have had more/better success sanding off the skin.

Les

[rcnewcomb]

Can you tell me more about the SplitStop screws? How do they work.? Where can I get them? etc.