Plywood Thickness and Cabinet Doors

Nominal quarter-inch plywood can really be 5 millimeters thick. Here are thoughts on accounting for edge thickness when machining the door frame groove.July 6, 2011

My supplier had no "true" 1/4" birch plywood for some cabinet doors I'm building. How do you deal with cope and stick made frames that have a 1/4" groove and your using plywood - veneer to fill the gap? Also, do I need another set of shaper cutters to mill my glass panel doors cope and stick? As you may have guessed, I grew up making mortise and tenon doors. The shaper cope and stick is new to me. I have a Freeborn set.

Forum Responses
(Cabinetmaking Forum)
From contributor G:
What you are getting now that they call 1/4" is really 5mm. You should be able to get a 5mm slot cutter for your cutters and the same spacer for the cope. Or you can get a 1/4" veneered MDF that should be closer to 1/4" then the 5mm.

From contributor F:
MDF core is the way to go for door panels. If you’re using the Freeborn six piece set you can essentially do three types of door. What you’re making now is the usual five piece panel door. A glass door can be made by switching the cutters. When you run your sticking cuts the profile is on top (at least for the sake of this example) then you have your larger diameter grooving cutter, then you substitute another same diameter cutter for the bottom cut. This leaves the frame open for the glass to be installed afterwards.

Finally - the open frame type of door. This is where you have no grooves, just a profiled frame for attaching to the front of a wine cooler. Similar to the way you do a glass door except instead of having two of the same large diameter cutters below the profile, you have two of the same smaller cutters. Obviously you change your coping sets in the same way. I hope the way I described it makes sense.

From contributor KD:
See if your supplier has 6mm baltic birch. I use it for paint grade and birch doors. It fits the 1/4 inch groove pretty well.

From the original questioner:
Thanks to all. I see now how to stack the cutters for glass. There were no instructions with the set. Also, yes, 6mm Baltic birch will work fine in the 1/4" groove. Most of my material is shipped as I'm an hour ferry ride away from all suppliers. They told me when I ordered that the domestic 1/4" birch ply would be 1/4". Now they say it can vary.

From contributor B:
For flat panel doors, I normally reverse a solid raised panel, or use 1/2" plywood and back cut it to fit in the 1/4" groove. For the price difference in 1/4" vs. 1/2", the quality of your finished product is well worth it. For glass panels, I just use a 3/8" x 3/8" rabbet bit with a bearing in the router to remove the rest of the material after the frame is glued up. I clean up the corners with a sharp chisel. It takes less time than changing to a dedicated setup on the shaper.