I'm building some 3x3x16" long L brackets out of 3/4" plywood. I'm planning on using a simple butt joint with a single rabbet and screws to attach the two pieces together.

The strips are all bowed/warped slightly. About 1/8" over the 16" length.

In my specific case, Without the rabbet, I could just glue, clamp, and screw the two pieces together.

If I try to rabbet the warped plywood, I'm afraid the depth of the rabbet will vary with the warping of the wood and then yielding

This could work for the rabbet as long as there is room above the fence for clamps, but what about a dado? straightened workpiece for rabbet

This seemed to work for a rabbet: enter image description here

Question: How can I rabbet or dado a warped plywood strip such that the depth into the wood is consistent? Convex side up or down? What if there's a veneer/finished side and there's no option to choose which side?

  • 1
    Clamp it flat ;-)
    – Graphus
    Commented Jun 28, 2017 at 7:11
  • yes. make it so.
    – aaron
    Commented Jun 28, 2017 at 11:11
  • I added a sketch, but that doesn't totally answer the question. Clamps can get in the way and screws may not always be favorable.
    – GisMofx
    Commented Jun 28, 2017 at 13:34

2 Answers 2


Use a router to make the rabbet or dado. You'd still run into problems if the warping of the plywood is significant even at the size of your router base, but if it's that badly warped you may not want to use the piece to begin with.

Clamp straightedges on either side of your dado, offset from your dado by the distance between your router bit and the edge of your router base. This will also serve to flatten the boards a bit more. If your router bit is not sized the same as your dado width (very likely), make it in 2 or more passes.


Clamp a strip of wood or metal parallel along the plywood near where the dado is to be cut. This hopefully straighten out the plywood and allow you to run it through the table saw and achieve a consistent dado depth.

  • A picture or sketch would be helpful
    – GisMofx
    Commented Jun 30, 2017 at 14:28

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