how much can plywood move?

[Steve knight]

I got a job I bid on to cut these part out of 3/4" marine mahogany plywood. they are rectangles that have a bunch of 3" holes in them that are chamfered.
the thing is they have a tolerance of +.01 I will have to make a gage to check the holes but the thing is could the holes change size with the wood movement when they are shipped more then that? I know ply can change thickness not sure about length and width.

[Jamie Buxton]

Plywood doesn't change appreciably in length or width.

Think about it this way... You want to make 3" holes, to a tolerance of .01". If a 3" hole were to grow .01", a 96"-long sheet of plywood, which is 32 times longer, would grow 32 times as much, which is .32" You've never met an eight-foot piece of plywood that somehow grew to be 96.32", have you? So you should be okay. Make the holes to the .01" tolerance, and they'll stay that way.

[Michael Simpson Virgina]

I think more of a problem will be warpage. I have seen even the best plywood warp more than .01 at that size.