Anyone ever tried these plans from B.C. Childress's '03 post

[billh]

Thanks Bill,

Talking about the D bore.

If the bell diameter is "normal" but the flare is concave as opposed to the more usual convex.

Err, "concave" is normal for (wide-bore) D chanters.

That would mean that the bore is wider than usual in the mid section of the chanter. And possibly the upper section too if the throat sizes are correct.

What are the implications of this?

Would holes sizes have to vary from the usual to compensate?
Would it have a more flat chanter timbre?
I've heard too wide a throat gives a gurgling Hard D.

David

This is all pretty general (regarding where the bore would be wider/narrower). I can't say for certain what the general implications of convex versus concave are, given the same approximate rate of taper and throat size. It's probably safe to assume that the two might want somewhat different reed/staple geometries.

"Everthing affects everything else" in this business, so by extension there's probably a set of counter-adjustments for any change that will in theory compensate.

I seriously doubt that changing the profile from 'concave' to 'convex' would yield a more "flat-chanter-like" timbre; the flat chanter timbre seems to be tied not only to the details of the bore perturbations, but the shallow rate of taper, small bore, and small reed. On the other hand, I haven't done the experiments to disprove the hypothesis, and "flat-chanter-like tone" is a pretty subjective thing...

A gurgling bottom D is one symptom of an over-wide throat, but it can be caused (and cured!) by other things as well. For instance I've seen it cured by increasing the reed volume above the staple.

regards

Bill

[John Mulhern]

Hiya Bill! Extending the two nearest reed seat line co-ordinates ( D.234, Z13.65 & D.219, Z13.51) and intersecting them with the two nearest bore line co-ordinates (D.234, Z12.08 & D.219, Z12.73)...the throat intersection is at D.204, Z13.372. I really hope this is what Bruce had in mind cuz I've already turned the dang reamer blank. LOL

http://bagpipereamers.4t.com/

[billh]

Hiya Bill! Extending the two nearest reed seat line co-ordinates ( D.234, Z13.65 & D.219, Z13.51) and intersecting them with the two nearest bore line co-ordinates (D.234, Z12.08 & D.219, Z12.73)...the throat intersection is at D.204, Z13.372. I really hope this is what Bruce had in mind...
http://bagpipereamers.4t.com/

Yes, that sounds a lot more typical, i.e. .204 = 5.18mm, actually about a thousandth narrower than usual. You'll have to ask Bruce I guess

[bcpipes]

John Mulhern wrote:
Hiya Bill! Extending the two nearest reed seat line co-ordinates ( D.234, Z13.65 & D.219, Z13.51) and intersecting them with the two nearest bore line co-ordinates (D.234, Z12.08 & D.219, Z12.73)...the throat intersection is at D.204, Z13.372. I really hope this is what Bruce had in mind...
http://bagpipereamers.4t.com/

Yes, that sounds a lot more typical, i.e. .204 = 5.18mm, actually about a thousandth narrower than usual. You'll have to ask Bruce I guess

This is correct. There is no cylindrical area anywhere in the bore. What you see on the graphs is simply due to not having any measuring rods that match the throat diameter precisely. As for the variations in the bore, concave vs. convex. That is accidental. My first attempts at reamers was to shoot for a perfect conic section. Subsequent tweeks of the reamer, based on what my ear was telling me, resulted in the variations you see. I cannot explain them. The ear is the final arbiter.

All this is why I cut my reamers out of 1/4 tool steel, and I don't harden them. Yes, they loose thier edge quicker. Yes, you have to take great care to avoid "chatter". But, you also have the ability to alter the reamer at will. My reamers look crude-as-hell, but I wouldn't part with any of them. Complete creative control is worth the previous mentioned problems. If you have someone tool and harden a reamer for you for $500, you are stuck with it, for better or worse.

[rorybbellows]

Subsequent tweeks of the reamer, based on what my ear was telling me, resulted in the variations you see. I cannot explain them. The ear is the final arbiter.
.

Is it possible you can give us an example of what you mean.Say you have a particular probelm with a certain note what might you do with the reamer to cure it ?

RORY

[bcpipes]

Is it possible you can give us an example of what you mean.Say you have a particular probelm with a certain note what might you do with the reamer to cure it ?

RORY

That depends on what the certain note is. With the notes: G, A and B (first octave) I have never noticed much in the way of the bore affecting them. I have always tuned, overwhelmingly, through tonehole size and placement. Other notes are a combination of Size/placement (tuning) and bore (timbre). The shape I have come up with is due largely to my insistence that a "hard D" be achievable without a small rush at the bottom (doesn't always happen, a lot depends on the reed, too) and a stable back D. In my early developement days, I tended to enlarge the throat to stablize the back D. This would throw the Hard D out of balance (as previously stated in this thread). I corrected this by reducing the cutting diameter at the bottom. I suspect the reduction increased the bore diameter (realatively speaking) slightly above the A note, as I started getting a raspy balky second octave A and E. Reduction there was necessary, all the while being careful not to change the throat diameter. Then, on top of it all, I have to maintain the staple-to-bore ratio for 1st-to-2nd octave tuning.

I altered the reamer with a 'fish scale" file during the developement times. Now, when I sharpen a reamer (with the fish scale file), I don't have to cut and try, like when I was developing it years ago. I just measure from corner to corner, along the reamer, to match the bore dimensions of my favorite chanter. During developement of a new reamer, I use Diamondwood or cocobolo to test it. It is not cheap if something goes terribly wrong. But, if the worst happens, it brings on fewer tears than blackwood, ebony or boxwood.

Of course, there is the reed issue. One note that I have found difficult to work out, bore-wise, is the second octave E being flat with respect to the first octave E. Raising or enlarging the tonehole fixes one at the expense of the other. So, it could be considered a bore issue. I don't go all John Bolton over it, because I'm happy with everything else and I don't want to risk making it worse, overall. But there are compensations in the reed that can reduce the problem. Namely, to give it a larger volume in the area just above the staple. That also, (as previously mentioned in another thread) lends to a more stable hard-D. It will also sharpen the second octave, all else being equal. See-Saw, See-Saw.

[bcpipes]

P.S. I have some idea as to what was going on in all this. But I can truthfully say, after some dissatisfaction with adhearance to other measurements, I cleared my mind and basically hacked until I was satisfied with what I was playing. Many chanter carcasses collect dust in a box on a far away shelf in my shop.

I don't want to sound like I've re-invented the instrument. I and others probably are more similar than dissimilar. There is still so much that I can't put a finger on. So, the measurements I have provided this list should not be considered, in any way, an end-all.

[Pete D]

David Lim,

I love that type of graphical information!!! Awesome to consider piping sounds in context more scientific. As there exists an entity we call “love”, science is not everything (if anything), but often, IMHO, many technicians, pipe makers and whistle makers included, neglect science.