I try to pay attention to expansion and contraction while engineering a joint. My problem now is trying to make a triangle. Should all three pieces be mitered at the same angle, or the top mitered and the bottom joints be butted? Will there be a difference? — Tom Kotowski
Chris Marshall: Tom, without a photo or drawing to see what sort of triangle you are trying to make, it’s tough to answer your question thoroughly. Remember that wood predominantly expands across the grain, not lengthwise. And, end-grain joints are inherently weak because glue tends to wick up into the pores, forming a poor glue bond. Keep these two factors in mind when designing your triangle. If it were me, I’d try to reinforce the joints with a mechanical connection of some sort (dowels, brads, splines, screws) or choose a joint that creates its own overlapping, interlocking connection. I wouldn’t count on glue to be the only hero here.
Tim Inman: To me, this is more an aesthetic question than a functional one. Most commonly, equal miters would be the norm.