Is 3/4 Birch Ply a Good Material for Furniture Bottoms?

[michael dilday]

I am building mid-century Modern dresser and tall chest. I used ply for the bottoms. The bottoms cantilever 4” past the legs on each side. Should I worry about the ply warping with the constant weight? The sides are bearing on the ends of the ply with no center support.

[Richard Coers]

Depends. Are the sides of the case plywood or solid wood? Gluing and screwing a plywood bottom to solid wood sides will result in the sides splitting when the wood shrinks. If the sides are plywood, you should enough strength from the sides and mainly the back, to give the bottom the strength. I'd probably go with at least a 1/2" thick back.The total weight and size of the case also makes a difference.

[Jim Becker]

I'm with Richard...we need to know more about how you are constructing your piece.

[johnny means]

Shouldn't be an issue unless you're filling the drawers with books.

[michael dilday]

I'm with Richard...we need to know more about how you are constructing your piece.

It is a Mid-Century Modern 5 drawer chest. 40" wide, 50" tall and 18" deep. No face frame. The 7" legs are inset front and back 1 1/2" and on the sides 4" with 2" high cross supports between them. Bottom is 3/4 Birch ply with 2 1/2 frontal soft maple. Sides are soft maple joined panels with a 1/2" wide rabbet 3/4 deep rabbet to accept the bottom and it is glued and screwed from the bottom. The top is 3/4 soft maple joined panel glued and pocket screwed to the sides. The back is 1/4" birch stapled to the drawer separator frame backs and 1/2" square back supports around the edge inset 1/4". Drawer fronts are inset 1/4".
Photos - 1 of 1.jpg

[Richard Coers]

The sides and top could move around 1/8" to 3/16" from season to season. If you don't remove the bottom now and change the construction, something is going to give when that soft maple expands this summer.

[kent wardecke]

I'm looking at a mid century piece right now. Ply wood and cantilevered.
I'll bet I watched norm abrams build a dozen pieces mixing hardwood and plywood. It looks well built and the dust frames add stability. I think you'll be OK

[Jim Becker]

Ok, so since the sides and top are made from solid stock, you really should make the bottom from the same solid stock, oriented the same grain direction as the other three sides. (presumably grain running parallel to front/back of the case) Why? Wood movement. If your case top and dust frames were also made of plywood, than a plywood bottom would be fine.

[Richard Coers]

I'm looking at a mid century piece right now. Ply wood and cantilevered.
I'll bet I watched norm abrams build a dozen pieces mixing hardwood and plywood. It looks well built and the dust frames add stability. I think you'll be OK

Norm was a carpenter and heard from a lot of critics who chastised him for ignoring seasonal wood movement in early episodes. In latter episodes he improved his methods by slotting holes and only gluing for a short distance in the middle or front so the movement could occur. Anyone can ignore laws of nature if they choose, but sooner or latter, nature wins.

[lowell holmes]

If I am making furniture, I use solid wood most of the time. It is fun looking for the wood you want. I normally go here.
https://www.clarkshardwood.com/

It's like I am a kid in a candy store.

[kent wardecke]

I'm looking at a mid century piece right now. Ply wood and cantilevered.
I'll bet I watched norm abrams build a dozen pieces mixing hardwood and plywood. It looks well built and the dust frames add stability. I think you'll be OK