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Cutting A/C plywood4/23
We seem to be doing a lot of parts out of A/C ply for various contractors in town these days. The obvious problem of getting ply of decent quality so that it's flat enough to stick down to the spoilboard has proved challenging.
Is it 3/4 material? Average size of parts? and is the whole sheet lifting or parts below a certain size?
You are right, a down shear version of your bit would be better for hold down, just remember to put the finished side on top. As you have probably already experienced, this may not be best as the sheet may hold down better one way and not so much on the opposite side.
You might first like to try leaving an onion skin or tabs, which may help depending on how warped the sheet is.
I have started offering my clients the option of tabbing all the parts and sending them back the sheet with the parts attached.
Most appreciate the cost savings because they have some kid in the back whose pay rate is a lot less than my shop rate.
Even if they have to bill their shop rate, it's usually 1/2 my cnc rate, so they come out ahead.
I have less scrap to deal with and less parts handling.
Thanks for those.
If you tab it and leave it as a sheet you can put screws in the corners.
Even you have to get your guy to cut the tabs it might be less stressful.
The way i do it is:
This is a bit of an art.
I tried a 3/8 downshear version of the upshear that you use. It worked great.
Ply usually has one side that holds down better than the other, so choose carefully.
I cut full depth less 1/4 inch on the first pass. It's amazing how often a sheet that won't sit flat will do so once a bunch of grooves 1/2 deep are cut in it.
And tabs. I use 1/4 thick tabs meaning that a section of the sheet can be 1/8 off the table and still not move.