Why back-cut panels?

[Jamie Buxton]

If you look at factory-built frame-and-panel kitchen doors which have raised solid-lumber panels, they often have a feature I've never understood. Functionally, the panel only needs to be thick enough to reach the back of the dado in the frame. However, panels are often thicker. The back of the panel often is co-planar with the back of the frame. With typical thicknesses, the frames are 3/4" thick, and the panel is nearly 3/4" thick, where it could be more like 1/2" thick.

The thicker panel obviously has a higher material cost, so why is this done? Is the panel somehow less likely to warp if it is thicker?

[Mike K Wenzloff]

Hi Jamie,

I think there are a few issues when it came to my shop. First is that most of my panels had profiles. In order to have the front of the panel even with the front of the rails/stiles, there had to be sufficient thickness.

Second, as most of my stock came in a skosh above final thickness, by processing all the elements to same thickness is a time saver. But, in order to have the panel even on both front and back in relation to the rails/stiles, back-cutting was necessary so the panel's tongue would fit the rail/stile grooves.

When I did Shaker and A&C doors, the panels were generally thinner than the rails/stiles. This meant extra dimensioning work for processing the panels. Which is why my bid was a little higher for those types of doors.

The issue isn't material cost...tis labor, consumables, and wear and tear machinery cost.

Take care, Mike

[glenn bradley]

Panel position in the rails / stiles based on panel thickness. If 3/4" and you want the panel proud, no back cut. If you want it flush across the front surface, back cut to match. I have seen 3/4" and 1/2" and other thicknesses based on need. There is no hard and fast rule that I can see.

[Andrew Williams]

Maybe the panels are cut planar with both faces of the frame in order to shove them through a wide belt sander.

[Howard Acheson]

>> Maybe the panels are cut planar with both faces of the frame in order to shove them through a wide belt sander.

Often the primary reason. The other being just aesthetics.

[David Eisan]

Hello there,

When I made my parents kitchen, Mom wanted a flat panel look on the front. The cheapest way would have been to use plywood, but it never looks like real wood. I could have used 1/4" real wood panels, but they sound "tinny" when the doors are shut and if you rap on them. I chose to raise the back of the panel to give it some mass.

Do a search on my postings and look for something about doors and my parents kitchen.

Thanks,

David.

[J.R. Rutter]

Cost is actually less to do it this way.

4/4 stock coming in, S2S to 13/16" (or whatever their spec. is.

Straight line and glue panels. (edge gluing station puts just the right amount of glue on)

Size panels and raise profiles.

Assemble doors.

Run through 3-head sander and orbital sander.

Run through edge profile / sand.

Finish.

If you don't go full thickness, you have to finish sand the panel back in a separate step...

[Steve Clardy]

I used to use 3/4 panels, and did the back cut with a rabbit bit.

Then I wised up to save a step.
I started surfacing my panels to 5/8
Lighter load for the door hinges.;)

[Jim Becker]

Some panels are 5/8" to account for offset. When I've "back cut" it's usually 1/2" material that need to fit into a 1/4" slot that is centered in the rails and stiles. You do what is necessary to work for the particular project...

[Jamie Buxton]

Thanks for the replies. So it seems that the reasons for the thicker panels have to do with ease of production, and not for a structural benefit.

[Joe Jensen]

The back cutter is to ensure that the tongue is 1/4". This way you can just flatten the panel, and as long as they are all withing 1/4" of each other in thickness, they will all look the same on the fonts.

When using the back cutter, the good face is down on the table when shaping. This way all panels have the same amount of cut, and then the back cutter makes sure the tongue is 1/4"...joe