Panel Door ???'s

[Greg Dykes]

I am using WoodShop Calculator door program and need some help on a few of the input measurements.

1. Center panel clearance: The S/R bit I am using makes a 3/8" deep groove. I have .26 spaceballs. What should be the center panel clearance?

2. Double doors-clearance between doors: I am using Blum 38N compact hinges w/ 3/8" overlay (part # 38N355C.06). I can't find any information on how much space I must allow between the two doors. Anyone know what the clearance should be?

3. The raised panel doors I am making will be painted for a kitchen. Would it be best to paint the panel prior to glue up? If nothing else, I was thinking of having my primer tinted to match the topcoat and paint the panels with that prior to finish coat.

4. I think I have a good idea on how I am going to build my coping sled. What I am not sure about is do you guys use some kind of sled when you are squaring up panels? The Miter gauge on my old saw is not the best. I was thinking of making a sled and running it against my "new $50 BIES fence" (had to gloat about that).

[David DeCristoforo]

"Spaceballs" should be compressed to 1/2 of nominal. With a 3/8" deep groove, that would mean that your panel should be 1/4" shorter than the corresponding rail in width. Calculate the height for the same clearance, so that the panel is 1/4" shorter than the distance between the bottom of the grooves in the rails when the door is assembled. I would shoot for a "reveal" of 1/16 - 1/8" between door pairs. Prime the panels before assembling the doors.

[Charlie Plesums]

"Spaceballs" should be compressed to 1/2 of nominal. ...that would mean that your panel should be 1/4" shorter than the corresponding rail in width. ....

I made a lot of doors using that "1/4 inch shorter. 50% compression" rule, but saw something fairly recently that said "...compressed almost 50%" and suggested 5/16 inch shorter. I have made a few doors with the 5/16 float, and like the lower compression and forces on the rails/stiles.

If your panels will be painted, I suggest that you use 5/8" MDF for the panel. It doesn't need the expansion/contraction room of solid wood, so no space balls, no gaps, and you can even glue in the panel if you want.

[Greg Dykes]

David & Charlie, thanks for the information. I was originally going to use MDF but decided not to for two reasons. One, the weight of MDF over popular. Some of my door are quit tall and I would have to add additional hinges because of the added weight. Second was the wear on my tools. MDF is a killer on bits and I have a lot of doors to do.

On the panel clearance I might take the advice you both have given and go with 9/32".