How to measure a chanter bore

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Jonathan_P
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How to measure a chanter bore

Post by Jonathan_P » Sun Sep 04, 2005 2:15 pm

Now that the “why?” question has been addressed elsewhere, it occured to me that no one (that I can find, anyhow) has asked for a detailed explanation of how to measure a tapered chanter or regulator bore. Specifically,

:: What tools and materials are required (and where to get them or how to make them)

:: Methodology

:: Things to avoid

:: Details that might be overlooked

David Daye has posted a page describing his measurement tools and technique at:

http://polarmet.mps.ohio-state.edu/~bda ... tcopy.html

I’m interested in hearing how others go about this task.

After reviewing some chanter measurement data published by Mr. Daye, Bruce Childress, Craig Fischer, Koehler & Quinn and others, I’ve taken the liberty of creating a draft chanter measurement worksheet and posting it at:

http://members.cox.net/jmparker/chanter_worksheet.pdf

Bearing in mind that I have not yet had a chance to measure a chanter myself (only some flutes and whistles), please feel free to comment on this sheet. I intend to make some further revisions, and will make it available to anyone that wants it for their own use. Perhaps a regulator data sheet will follow.
Jonathan

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djm
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Post by djm » Mon Sep 05, 2005 9:55 am

Do a search on the net for bore gauges (sometimes spelled "gages").

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Post by Jonathan_P » Mon Sep 05, 2005 11:37 am

djm wrote:Do a search on the net for bore gauges (sometimes spelled "gages").
Thanks for the response.

All of the commercially-available bore gages I've seen have metal contacts. No responsible museum official would allow me to insert one of these tools into a chanter's bore, as is proper to their role as guardian and conservator of these objects. Have you ever seen one in use? Can you point out exactly what tool was chosen for the task?

Also, the commercially-available deep-hole split-ball gages (there's a mouthful of hyphens) that I have found cost thousands of dollars each, and have a limited compass, requiring more than one tool to cover the range required in this case.

I've seen a very clever and efficient arrangement made by a flutemaker who measured many of the finest old instruments in European museums. It consists of two nylon half-ball-shaped contacts on the ends of long, thin arms, with a strain gage at the point where they connect. This is wired to an analog linear servo-driven pen, which plots the amplified shape of the bore across a sheet of paper. The paper is physically connected to the contact mechanism with an alligator clip, and as the probes are drawn out of the bore, the amplified bore profile is simultaneously drawn on the paper. Then the instrument is rotated axially 120 degrees, and the process repeated twice, showing the maximum and minimum diameters, as well as the interior location of the tone holes.

Perhaps something similar could be devised for chanter bores, but it would be difficult. The uilleann pipe chanter bore is smaller and longer, requiring longer, thinner probe arms. This would induce flexing, which is difficult to compensate for in an analog system. Perhaps if the strain gage is connected though a digital interface to a laptop computer, and the software is calibrated to compensate for the flex in the probe arms... But this is way beyond anything I'm going to build, or most instrument makers would want to take on.

As Bill has pointed out elsewhere, it seems that you have to make your own bore gages.
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Post by djm » Mon Sep 05, 2005 1:18 pm

I'm pretty sure I have seen buried somewhere in David Daye's many pages a description of a series of probes made of plastic. They consist of a plastic rectangle of a specific width. Each plastic rectangle is mounted on the end of a plastic rod. These are used to probe to as far in as they'll go, and you measure off the end of the rod to get the depth. They are an engineer's tool. I have not had need for them, so I did not write the details or maker down, but I'm sure the info is out there somewhere.

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Post by billh » Mon Sep 05, 2005 2:40 pm

go back to the 'why measure' thread, or maybe it was the regulator reamer thread... I posted a link to an imagestation album that included images of delrin probes.

Image
Image
Image

There are various ways of measuring the insertion depth. One that works nicely (thanks to DMQ for suggesting a variant of this) is to cut all the probes to the same length, then make some sort of cradle or stop, set up with a long metal rule, so that the end of the chanter is accurately positioned at the same distance along the rule as the length of the probes. For instance my probes are 495mm long, so I arrange a stop so that the chanter bell rests at 495mm on the rule. I can then read the insertion depth straight off the metal rule, as the distance where the far end of the probe ends up. Be careful of parallax, and try to use a nice accurate rule; 0.5 mm insertion depth would be a good goal, it's tricky to do a lot better but it may be possible with a vernier and some sort of constant-insertion-pressure gauge.

You'll also want small-hole gauges Image
for measuring the throat and toneholes. Those are always metal, but you can put a bit of flexible/stretchible vinyl or rubber tubing over them if you like. Just using a very light touch should be enough, though finicky museum curators may prefer them wrapped.

IMO the 'T' gauges have the disadvantage of not being stiff enough to get a good depth reading. Also I am not sure about accuracy.

If you have an engineering lathe you can machine the gauges; even if you can't get them to within 0.01mm or something, you can make them to nominal diameters (like 4.1 mm, 4.2 mm, etc. etc.) then measure them afterwards to determine their "actual" diameters.

Be warned that conventional verniers and digital calipers are only good to about 0.02mm, digitals usually only 0.03mm, which is not ideal. It may be worth getting a micrometer to measure the probe ends with.

Of course you can make just the heads as cylinders or discs (I worry about the accuracy of the disc method), and attach them to some shared shaft or stick. This slows the process down and may introduce some error, but it's of course more compact and no doubt faster to fabricate.

Bill

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Post by Jonathan_P » Tue Sep 06, 2005 3:40 pm

djm wrote:I'm pretty sure I have seen buried somewhere in David Daye's many pages a description of a series of probes made of plastic.
Follow the link in my initial post in this thread to find pictures of David Daye's probes and an image of them in use.
They are an engineer's tool. I have not had need for them, so I did not write the details or maker down, but I'm sure the info is out there somewhere.
Daye made them himself. I've followed his instructions, and tried his technique on a wooden flute. I have to agree with Bill's assessment that this style of bore probes are not stiff enough, and thus make it difficult to get an accurate reading.
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Post by Jonathan_P » Tue Sep 06, 2005 4:52 pm

billh wrote:There are various ways of measuring the insertion depth. One that works nicely (thanks to DMQ for suggesting a variant of this) is to cut all the probes to the same length, then make some sort of cradle or stop, set up with a long metal rule, so that the end of the chanter is accurately positioned at the same distance along the rule as the length of the probes. For instance my probes are 495mm long, so I arrange a stop so that the chanter bell rests at 495mm on the rule. I can then read the insertion depth straight off the metal rule, as the distance where the far end of the probe ends up.
This is just the sort of information I was trying to dig up. Thanks to David for sharing that idea, and to you Bill for passing it along.
You'll also want small-hole gauges for measuring the throat and toneholes. Those are always metal, but you can put a bit of flexible/stretchible vinyl or rubber tubing over them if you like. Just using a very light touch should be enough, though finicky museum curators may prefer them wrapped.
I was able to get a nice set of Starrett small-hole gages on eBay a few days ago for a very reasonable price. They could easily be covered with tape if the situation demanded it.
IMO the 'T' gauges have the disadvantage of not being stiff enough to get a good depth reading.
I made some of these a while back just to test the concept, and I agree with you.
Be warned that conventional verniers and digital calipers are only good to about 0.02mm, digitals usually only 0.03mm, which is not ideal. It may be worth getting a micrometer to measure the probe ends with.
Too true! I have long used a dial caliper for woodworking, but when I started turning on the metal lathe I was dismayed to find that they were not accurate enough for this work. I now have a couple of micrometers, and am shopping for a dial gage to set positions accurately on my lathe carriage.
you can make just the heads as cylinders or discs (I worry about the accuracy of the disc method), and attach them to some shared shaft or stick.

This idea had occurred to me as well, and I may give it a try. The trick would seem to be registering the detachable part accurately on the shaft in a repeatable way. If they had a recess to snap the shaft into, or were threaded with a shoulder, it may be possible to keep them uniform in length.

Thanks for the ideas, Bill.
Jonathan

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Post by dirk the piper » Wed Sep 07, 2005 11:33 am

I'd like to go ahead and ask the other side of the "how" question. Other than hoping and praying for a special opportunity, how can we arrange to borrow a good set of pipes to measure? I wouldn't expect anyone to trust me with measuring a historic set unless I could first prove my skill at responsible measuring. On the other hand, measuring the work of a living maker might be ethically questionable. Thus, I'd like to thank those kind people who have the knowledge of the better old sets and who have published their measurements for the benefit of us all.

How can we be sure of the quality of a certain set of measurements that are made? Wouldn't somebody need to successfully build a set of pipes based on those measurements? It seems to me that if measurements are made, and some really good sets are built from those measurements, that information about the new sets could then be added to the measurement data sheet as a testimony. Just a line at the bottom - so and so made a set numbered X based on these measurements.

-Dirk
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Post by djm » Wed Sep 07, 2005 11:55 am

There's a fellow in Denmark selling plans for several old sets. Price is approx US$50 and up. I have not purchased any of these drawings so I cannot speak to the accuracy/value. Caveat emptor: http://www.bagpipedrawings.webbyen.dk/

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Post by billh » Wed Sep 07, 2005 11:59 am

dirk the piper wrote:...
How can we be sure of the quality of a certain set of measurements that are made? Wouldn't somebody need to successfully build a set of pipes based on those measurements? It seems to me that if measurements are made, and some really good sets are built from those measurements, that information about the new sets could then be added to the measurement data sheet as a testimony. Just a line at the bottom - so and so made a set numbered X based on these measurements.

-Dirk
Yes, exactly. I only know of a few examples where we can really say this, and it's important.

For instance, there is a set of measurements published in the Iris na bPiobairi/Pipers' Review in Autumn 1999, for a Leo Rowsome boxwood chanter owned by John Hughes of Newtownabbey (Belfast area). The measurements were taken by John, and I've seen his measuring technique and so I believe the measurements to be very good. However I have not personally attempted to use those measurements to make a chanter, and I don't know of anyone who has offhand. Probably/hopefully someone has. This means that if I want to know how they work, I'll just have to do the experiment and see. (Though to be honest, in this particular case I have the advantage of being able to drive up to John and try to make a reed for the original, to see what it's like - usually that's not possible).

Several problems arise. Sometimes makers are reluctant to cite their sources, sometimes makers choose to take a shortcut for some reason or move toneholes around, etc. and thus aren't really making "copies", sometimes makers claim to be making a copy but in reality are deviating in significant ways which they don't want to explain publicly. Perhaps those of us with an experimental and/or hobbyist bent will be left to provide the public evidence.

I do know of a few sets of data that have worked out well for one or more makers, but those measurements are unpublished. I'm with you, I'd like to see more reports of the direct experiences of makers with the few published data sets.

Joe Kennedy has said (publicly) that he used the drone measurements for the Kenna C in SRSv2 successfully; I heard and played the resulting set and it certainly did seem nice, I plan to try the Kenna C drone data myself before too long. However I believe that the chanter Joe made for the same set may not have had the Kenna bore (hope I'm not giving away any secrets by saying that!).

Bill

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Post by Jonathan_P » Wed Sep 07, 2005 2:18 pm

billh wrote:I believe that the chanter Joe made for the same set may not have had the Kenna bore (hope I'm not giving away any secrets by saying that!).
Since Ross, its owner, has publicly said that Joe used a Coyne bore for that chanter, nobody can accuse you of any impropriety in this case. It's a very nice looking set. I see that you've played it, too.

http://chiffboard.mati.ca/viewtopic.php?p=386449

As regards the fellow in Denmark, he seems a bit cagey. When I asked a year ago, he refused to give me a price list for his plans, insisting that I tell him which ONE plan set I wanted before he would give a price. Then he wanted me to order that set before he would tell me the price for another.

DMQ has publicly commented about the plan this fellow offered for a Bb chanter supposedly based on an instrument by David Quinn, but I'll let him speak for himself. I agree with DJM. Caveat emptor.

Has anyone here purchased plans from this source? Care to comment on the bore measurements contained in them (steering this back onto topic)?
Jonathan

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Post by djm » Wed Sep 07, 2005 3:02 pm

I think he is maybe a bit greedy. I got the same rigamaroll about not wanting to publish a full price list, so I sent him a list of all the plans I might be interested in (basically anything not Rowsome). Here is what I got (in Danish Kroner):

Keyless chanter in B, based on T. Kenna: 245DKR.
Keyless chanter in B
<= whose chanter is this based on? on B.Chidress: 210 DKR
Keyless chanter in Bb based on J. Bourke: 210DKR
Keyless chanter in C, based on M. Coyne.: 245DKR
Keyless chanter in C
<= whose chanter is this based on? on E.Lambe: 245DKR
6 keyed chanter in C from ca. 1830 based on Thomas Kenna: 550 DKR
1 keyed, B key, chanter in C based on M.Coyne :280DKR

Post and Package extra :100 Danish Crowns.

All expeditions are made by air mail.


You can work out whatever that means in your own currency here: http://www.xe.com/ucc/

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Post by dirk the piper » Wed Sep 07, 2005 4:45 pm

That's interesting. BC recently posted some of his B chanter measurements on C&F. Do you suppose it's because of this guy?
-Dirk
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Post by djm » Wed Sep 07, 2005 5:12 pm

I would not venture to guess what Bruce may or may not have meant to do. It may simply be that he was trying to be helpful. You would have to have a particular liking for his pipes for the drawings to have any value to you.

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Post by DMQuinn » Wed Sep 07, 2005 7:03 pm

Jonathan_P wrote: ...
As regards the fellow in Denmark, he seems a bit cagey. When I asked a year ago, he refused to give me a price list for his plans, insisting that I tell him which ONE plan set I wanted before he would give a price. Then he wanted me to order that set before he would tell me the price for another.

DMQ has publicly commented about the plan this fellow offered for a Bb chanter supposedly based on an instrument by David Quinn, but I'll let him speak for himself. I agree with DJM. Caveat emptor.

Has anyone here purchased plans from this source? Care to comment on the bore measurements contained in them (steering this back onto topic)?
Just as sort of a stroll down memory lane, I went and had another look at this fellow's offerings just now. Imagine how crestfallen I was to find that he was no longer selling drawings of the B-flat chanter I never made. That may indicate that he has read or heard about previous discussion of his offerings on that other UP forum.

I've seen and heard enough that I would give this fellow and his drawings a wide berth, but that's not to say I'm not curious. I'd want to know a whole lot more about the bore data provided with any of these drawings before I'd spend money on one.

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