Cabinet Doors Twisting in the Clamp

A cabinetmaker tries to understand why door parts twist out of alignment during the assembly process. January 11, 2008

How does everyone attach their cabinet doors? I have all the pieces ready to assemble. I also have a door machine for assembly. I normally glue the stiles and rails and then, when JLT door machine squeezes everything together, I pin nail them. Problem is sometimes rails and stiles want to roll a little on the front side. I normally pin nail on back side. Last set of doors, I put a few pins in front side and it worked better, but when I ran doors through sander, pins wanted to show in places. I thought about dowels to hold more straight, but that sounds like a lot of work. Any suggestions?

Forum Responses
(Cabinetmaking Forum)
From contributor K:
Adjust your shaper cutters. Something is not cutting right. If everything is cutting square and your stock is perfectly square, this should not happen. I had one shaper spindle that was not perfectly square with the shaper table and it gave me the same thing.

From contributor J:
Also check pressure regulator on clamp. If you are putting too much pressure on door, it will roll on you, too. Also, make sure that whoever is clamping and pinning the doors is allowing the clamp to fully open before removing the door. If they get ahead of the clamp and don't allow the horizontal clamp to fully open, when they grab the door top to remove, it is real easy to roll the door and break it.

From contributor R:
Try making them twist toward the back side, then the wide belt or drum sander takes care of it. Sloppy cutters or over clamping makes mine do the same with bar clamps, even brand new cutters with too much clamp on them and they will roll. I have found the softer the wood, the less clamp pressure they will withstand.

From contributor P:
I don't know anything about a JLT door machine, but it sounds like the clamping force is uneven. I use parallel jaw clamps, Jorgensen and Bessey, which pretty much eliminate the twisting problem you have with other clamps. So maybe the clamping mechanism is in need of adjustment.

From contributor C:
Clamp pressure, closure speed of clamp jaws, and type of material can all play a role in this. We have both an air unit like yours and a clamp rack... Both will show the problems you describe.