I am building a small woodshed to get some practice at square rule layout, and I am drawboring all of my joints. The method I use is to drill peg holes in both mortices and tenons at the time I cut the timber in the "shop" (snow-filled backyard). I simply lay out the same point on both the mortice and the tenon, then offset that point on the tenon by an eighth in the (hopefully) correct direction.
I don't know if I read somewhere that this works well, or if I am just being lazy. My take is that, as long as I drill my mortice peg holes close to perfectly square, they should correctly misalign with the tenon peg holes upon assembly. I will be using tapered pegs, so there should be no problem engaging the offset peg hole.
There is still the question: how consistently can I drill my peg holes square? I can see a situation where the peg engages the tenon hole but won't pound in much further because of sloppy drilling, and ends up putting fairly localized pressure on one point of the peg and/or tenon relish. I suppose this could also be a problem if the "double assembly" drawbore method is used. If your initial mortice peg hole is out of square, you'll have to mimic that angle as you drill your tenon peg hole freehand.
My question is, does anybody else out there do what I am doing? Has it worked well for you, or am I in for a surprise? Is it as persnickity as I am making it out to be? I do like my method more because it is easier -- no drilling on assembly day.
