Hi Michael,I am getting confused and have to ask about definitions:
what do you mean by "chimney height"? I used to think this was the wall thickness at a certain fingerhole, but "back d chimney should be around 10.0 mm" makes me think I must be wrong.
And what is this measurement: "at 262mm I would expect reeding it to A=440 might not be too tough"?
It is a measurement that is meant to imply the correct wall thickness, but it does so with the depth of a probe into a tone hole. If one has already made an accurate measurement of the bore, you can make it easier to measure the amount of scalloping on a tone hole by inserting a small probe with one rounded end into the tone hole until the probe rests in the inside of the bore. This measurement has produced reliable results, and is what is meant by the "chimney height." I think I might have heard "stack height" before, too. It's a much simpler measurement to just insert a probe than to try to get the thickness with calipers, or something. Besides, if the tone hole is rounded, or undercut, and the bore is tapered, it's going to be even more difficult to accurately measure the wall thickness any other way.
For instance, on a scalloped D back hole (for a concert-pitch chanter) you might see a chimney height of around 8.5 to 10mm. A couple of less-scalloped chanters I own have a back-d depth of around 11mm.
I'm not sure what the number "262" means, now that I look it up, and the chanter in question is 362.5 mm long. Or maybe we are talking about an alternative placing for back D? I think that Bill means that the seemingly short overall length of 362.5 should still make it possible to make a reed for the chanter such that it will be in tune with the modern concert pitch where A=440 Hertz. In the old days, the conventional piper's tuning used to be higher, so probably Leo Rowsome played an A that was pitched a bit sharper at around 444 Hz, or maybe even higher than that. I think I remember that the Chieftains like to play at around A=447, to match the pitch of Paddy Maloney's chanter, which I understand was also made by Leo Rowsome. You can read more about where and how the pitch standards and conventions changed in space and time here: http://en.wikipedia.org/wiki/History_of ... tern_music.