cross-grain problem

[Don Voegel]

I will be making some large doors for an EC and the top rails will be 12" in width (with a quarter-circle cut out). Since this is a wide cross-grain situation, how should it best be dealt with?
Thanks, Don

[Jamie Buxton]

You probably shouldn't glue the entire 12" lumber width to a cross-grain member. I'd use a tongue-and-groove joint, but only glue or peg part of the joint. Biscuits are another easy way to do the same thing. The rest of the door needs to deal with the fact that the 12" plank is going to be moving.

You might also consider doing something this wide in veneered plywood. It won't expand and contract, and it won't warp. Particularly in doors, warp is a big issue. Unlike casework, where other pieces help keep lumber straight, doors have nothing to keep them flat. If the 12" lumber chooses to twist a little bit as it is expanding and contracting, the door will warp.

[Richard McComas]

If you want to use solid wood for your stiles and rails (I would) you could use the breadboard type design. As the other poster suggested use a tongue and grove but I would also add the mortis & tenons to that idea give you the strength you need for a big doors.

When you make the mortises you make them long so the tenons can slide back and forth with the wood movement.

This bread board process is written in detail in Fine Woodworking # 110 if my memory is correct.


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