There is such a thing as a drift drill, which is a small burr bit at the end of a flex shaft, encased in a rigid but bendable tube. Luigi Viprati uses this sort of arrangement for many of his dramatically curved shanks. But, I don't think it was necessary here. If you imagine the tobacco chamber angled rearward, which it would have to be in order to be of a decent size, I think there's actually a straight line that goes from the mortise to the bottom of the imagined chamber. Obviously, the draught would not be coaxial with the mortise itself, would skate dangerously close to the upper curve of the shank, and the probability of screwing up is relatively high, but it could be done by the right guy, and it would appear Lasse is one of those right guys. I've often been amazed by some of the pipes that I was positive MUST have a curved airway, but turned out straight. Not saying this IS one of those, but it could be, if just barely. Neat work!
