How consistent are thicknesses of various types of plywood?

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Forum topic by Bob in Salem posted 06-09-2009 06:46 AM 971 views 0 times favorited 2 replies Add to Favorites Watch
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Bob in Salem

6 posts in 3276 days

06-09-2009 06:46 AM

I just bought a bunch of 5×2 ft sheets of 1/8” Baltic Birch and I’m finding the thickness various from .110 to .125”. My project utilizes push together slot joints that can be taken apart and put back together. Ideally I’d like the pieces to be snug enough to stay but not so snug you can’t get it together or apart. I’m using my new digital caliper and wondering how I got by without one. However, if I could find a source for some ply that is more consistent I’d switch to that. I tried a sheet of meranti 1/4” or some metric thickness, (4 mm?) can’t remember but it seems to be more consistent than the birch. Uglier but more consistent. I’d rather not get any thicker than 1/4” Any ideas?

Also, I noticed how one small piece that sat out in the rain overnight swelled to about twice its thickness then within a day it was almost back to normal.

I live in Oregon and one day it’s 80 degrees and the next day it’s cold and rainy. I’m guessing this stuff fluctuates more than I know.

-- - - Ever notice that all tape measures are left handed? - -

2 replies so far

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686 posts in 3282 days

#1 posted 06-09-2009 07:29 AM

I’ve had problems with ply I buy from places like Home Depot, but when I buy a high quality (and more expencive) ply from a hardwood dealer I have less problems. I have had problems when I buy ply at different times, I don’t know if it needs to acclimate or if it varys from one unit to another.

-- I didn't go to college, I was too busy learning stuff - Ted Nugent

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Bob in Salem

6 posts in 3276 days

#2 posted 06-09-2009 07:48 PM

Thanks for the advice. I pretty much did that today as I’m finding until my Craftsman Molding Cutter comes I’ve got to do two passes with my Ryobi B3100 which is pretty accurate but in the 1200 slots I just cut in the last half hour I doubt I’ve held incredibly close tolerances. I’ve come to the conclusion that if one piece is two tight or two loose, find another one that fits. In one of my kits there are at least 16 of any one size piece so that’s how it’s going to be.

I did find a Plywood Company in Eugene Oregon called Murphy Plywood and they make custom sheets to very close tolerances. Looked like an interesting company if I was doing mass production. Maybe if my product takes off!

-- - - Ever notice that all tape measures are left handed? - -

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