Square plywood

[Greg Plouvier]

Not sure if this has been covered already - couldn't find any recent threads. Just a quick tip for builders without a lot of experience.
About 50% of the time the plywoods recommended for these builds will not be square. Baltic is notorious for this as well as not having straight edges. The Arauco is often not square either. What I do is check the corners of the sheet with an accurate framing square. If you find a square corner, mark it and start your cuts referenced to that corner. Also check the edges related to that corner for straightness. Then I re-check the ends after the initial rip. If you can't find a square corner, make your initial rip, referenced off a straight edge, then square up an end with your circular saw and sled and work off of that end for your other cuts. How do know if your framing square is accurate? Put one side of it against the edge of a straight piece of ply 16" or so wide, and mark a line along the other edge across the ply. Now check the line from the opposite side of the piece and it should be parallel with the square edge. If not - square no good.
Squaring your ply will go a long way towards a less frustrating build and a nicer end product.

[LelandCrooks]

+1

[SeisTres]

+1

REALLY?!?! I thought that they were as squared as one could hope for?

[BrentEvans]

I watched a "how it's made" type TV show on lumber and plywood once... at the speeds that stuff goes through the mills, it's amazing it's as square as it is.

[LelandCrooks]

4x8 sheets are almost always square. 5x5 stock needs to be checked.

[SeisTres]

4x8 sheets are almost always square. 5x5 stock needs to be checked.

phewww! in that case, I'll keep using most of the edges of the plywood first. thanks for the update.

[DrDoug018]

4x8 sheets are almost always square. 5x5 stock needs to be checked.

So THAT'S why my cabs don't come out perfect

I feel better.

Doug

[AntonZ]

I cannot haule large pieces of ply. So I have the guys at the shop cut to managable pieces on their big vertical machine. I always have them start with a 1cm cut (1/4" to 1/2" will do, too). All subsequent cuts will be exactly parallel to this first cut. Same procedure for first cut on the smaller pieces, if they need further ripping. It works for me. The big machine in the shop was set up square, that helps.