If you are sure the joint is in compression, then the pin really isn't doing much, but it's common practice to go through both no matter what. Going through only one side is fairly useless, in my opinion. A pin should be in double shear, not only for strength, but so that the pin is evenly supported. If it were only going through one side, it wouldn't necessarily be in single shear only. There would be a moment(torque) that would be applied to one side of the mortise. Why are you asking this question, something specific?
I suppose you could bore a blind hole in the second side of the mortise, if your intent is to not have a hole and peg visible on the opposite side, but you'd have to do some peg adjustment to make the peg fit correctly without bottoming out. There would be a slight reduction in the strength of the joint.
Last edited by brad_bb; 08/12/10 02:48 AM.
