I've been making my own cabinet doors for the last 3-4 years. After reading about flat doors, I'm wondering how most cabinet doors are made. After getting disappointing results with S2S1E lumber, I've been buying rough cut and doing the following:
1. Rough crosscut
2. Rough rip
3. Face joint with power feeder
4. Thickness plane
5. Edge joint
7. Final crosscut
10. Thickness sand
Am I wasting my time with stock prep, or am I saving callback hassles? Should I be pushing this issue as a quality thing with clients: "I build doors the old-fashioned way", or is it a non-issue?
From contributor S:
I'd say your way is the best. If you’re producing doors for an overlay application, where concealed hinges have wide range of adjustments for cheating the door flatness imperfections, then hand picking s4s material for straightness will probably suffice.
1) purchase lumber hit or miss @ 15/16"
2) rip to 1/4" over fin. width. (some shops only rip to 1/8" over fin. wdth.)
3) surface to 7/8" from worst side.
4) finish crosscut to length.
5) cope rails
6) mill sticking edge plus 1/8" waste
7) mill outside edge parallel to finished wdth.
All of the steps you indicate survey the purpose of solving a condition in working the wood that's always there. And so you do have to do those steps as you describe, or find a way for the machinery to automatically do them for you. I find for example, I can simply select out of my SLR2E stock the straightest and flattest stock for the longest pieces I need (by the way if you don't already do this, cut part lengths from longest to shortest).
I then work my way down to the smallest pieces where a little bow or bend in the piece will automatically mill straight because of the way I have modified my fences, thus eliminating the one step of pre-straightening, and so on. If you don't have a wide-belt or drum sander, flattening and straightening as you do is a must - simply for a good surface quality when it is time to sand. You should always push the issue of quality when you have some over the other guy, but the customer doesn't care how many steps it takes to build a door, but how does it look?
I don’t need or use rub bearings, I burn an 1/8'' on the stile cut so the door stock is 2 3/8''. The panels are then dry and I cut them to size and run them on another shaper stacked with a panel raiser and edge profiler. Once the are on the assembly I glue my rails, slip them into the stiles, flush them up, and pin nail them. It is a lot easier to flush them up and tack them than to flush them up with clamps and then pin them.
The clamps override the pin nails and pull the joints tight. I lay the clamps flat on the table because that eliminates cup problems, and since the rails and stiles are 2 3/8'' wide, I have 1/8 to play with squaring them up on the radial arm saw. If a sile gets trimmed down to 2 1/8'' wide in the middle because it was bowed, it's on the inside edge, not on the outside where it shows up. I can square up a set of doors in just a minute on the RAS – a lot faster than I can run everything through the joiner. I then edge profile and run them through the drum sander, and then sand the face side first. Running them 2-3 light passes gets them very flat. I then sand out any thickness difference from the stiles and rails, and hit them with the orbital and I’m done.
Contributor R - Good advice to start eliminating steps. I'll start by going to 15/16" H&M on all of my lumber. I already crosscut all longer parts first with the straightest stock.
Contributor F - For face (and edge) jointing with the feeder, I run all wheels on the out-feed side, so that they reference off of the already jointed surface. This ensures that the wood is really flat. I am also using an outboard fence for sticking cuts. I edge sand all frame parts by running them between the table saw fence and a special sanding disk. This straightens the outside edge as well, if it has bowed when ripped. The sticking cut makes the inside parallel to the outside, and brings it to final width. I use various plastic spacers to set the outboard fence, and my shaper fence never moves. I cut all parts to finished size, so assembled doors just need a light hit at the ends of the stiles to remove any glue squeeze out.