The following is in response to a question about 'drawboring' a mortise & tenon joint. Author's names preceed their answers.
A drawbore is a tenon pinned from the side; but instead of assembling and driiling straight thru the joint, you offset the
holes a teeny bit, like 3/64 inch. Then hammer in a chamfered peg at glue up (or a tapered one -- 3/8 inch walnut tapered nails are my
trademark) and the pieces are drawn together, putting the M&T joint under tension & tranferring pull-out strains from the glue
faces to the peggy. Not that much extra work, if you use round nails. S-loads more if you go [with] square [pegs].
I find a taper of about 5 degrees is plenty on the peg; more that that, you'll have trouble driving it home or will as Dave says, blow the end off your tenon.
Some tips on drawboring:
[The] trick is to pound as deep into the far wall as possible without breaking thru the backside, giving the peg the broadest possible shelf to sit on. One helpful jig is a 1/4 inch thick piece of wood with a fence on one edge and a good square sample hole cut [at the] right distance. You can drill your holes with a forstner (best for flat-bottom, won't overfeed like a bradpoint), center the square hole over the round, & use it to guide your paring chisel. Practise lets you do it by eyeball pretty good.
Dave Mount -
One other thing to be aware of -- it is possible to break your tenon doing this if
When you pound the peg, you are pulling the tenon in by pulling on the side of the hole toward the end of the tenon. Obviously if the strain here is too great, you can break out the wood along the grain toward the end of the tenon. Don't mean to scare you off the technique, because it doesn't happen under ordinary circumstances; just keep your offset small (1/32 to 3/64 inch as Bob suggested). Moreover, with modern glues, even if the thing does break, you can clamp it and the loss of strength will probably not be an issue.