I could also optionally plane down the ends to try to take some of the concave bow out of the primary reference face, if I want to, if it's excessive.
A while ago I discussed this with a friend and former timber framing teacher of mine. He said that you can plane down the ends some, but the limit is the amount you're going to reduce the timber to make a joint. So for example if your general frame rule is 1/2" under the size of the timber then 1/2" is all you can plane off the ends to try and straighten it out.
If you plane off more then you're going to be under size on your joint on the ends.
I thought at the time that idea made sense to me....
Jim Rogers
