Quality Control for Five-Piece Doors
Basic information on achieving acceptable dimensional tolerances and fit when making cope and stick raised-panel doors. January 2, 2014
I do not have an overhead sander. After glue-up stiles and rails may be 1/32 or less from perfect fit. Other than using my ROS, what do people do without an overhead sander? What are some of the techniques for keeping everything flat and not making any valleys, etc.?
From contributor I:
Sharp and tuned #4 hand plane.
From Contributor G
1/32" mismatch between cope and stick is huge. You need to make sure your setup is better tuned in. You should always try to do everything face down so that is the reference side. Sounds like you are doing things back side down on the shaper and your material thicknesses are inconsistent. Getting the thicknesses of the wood stiles and rails closer will improve your work flow better. The closer you can get the stiles and rails level to each other the easier everything will be after that.
From contributor R:
I agree that 1/32 is too much. When I first started, a router table, then a 3/4" spindle 3HP shaper I aimed for - at most paper thickness difference. I knew how much turning the height wheel five minutes on the clock raised the spindle. It really didn't take long. Then, believe it or not I used a handle belt sander with, if I remember correctly, a 150gr belt. It does take a bit of practice, but you'll soon be zipping through them. If I had an errant joint that had more offset, I would sand it diagonally and feather it out. Otherwise, I quick trip over the rails and across the stiles, again with a bit of feather up the stiles if needed, to level out and remove planer marks. Then up the rails to take out the planer marks and the cross grain scratches from sanding the rails.
To keep things flat, get a power feeder. Because of the even feed, it will pay for itself in better finishes on the shaped material and will increase tool life. It is much safer. One trip to the emergency room is much more expensive than a power feeder. It will save in wasted time and material due to re-makes. For the cope cut, get some T-clamps and make a jig. When money comes better (must be an issue, you don't have a wide-belt) then you can get a panel crafter type jig. Now another stand on the soap box: A wide belt sander, is one tool that will pay for itself in a short hurry.
From Contributor K
A few things to do: Buy your lumber in the rough and be sure it is dried properly. Cut all parts to rough length and to rough width, then face and edge on a proper joiner, then plane to thickness and rough width. Buy and use a digital caliper. Select faces and run these on rigid reference points - like the shaper table. Use a real miter saw or dedicated cutoff saw for lengths. Record setup data on a sample for reference the next time you use the pattern. Know how your shaper fences work and how to tell if they run true or will make tapers, and why. Clamp up flat - start flat and stay flat. Clamp up square - start square and stay square. Sand with r/o sanders and then hand work the corners. The above is just the very basic stuff. You need to look at everything you do with a critical eye - assume it is wrong until you know why it is right.