 The Clarinet BBoard
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Author: bill28099
Date: 2004-02-16 17:51
I've just spent close to 2 hours searching this site for some standard method of measuring clarinet bore diameter and seem to have come up with none.
What is acceptable?
Here is what I have done for my antique and a half Bb Buffets. Using a telescoping gauge I go down the top and up the bottom of the upper section by .560". Then three measurements are taken at 120 degree rotations and averaged. Measurements are made with a set of 6" digital calipers.
On a 1953 the upper measurement is .576" and the bottom .569"
On a 1919 the upper measurement is .585" and the bottom .582"
From the above data what would one use for a bore diameter? How come the upper measurement is bigger then the lower?
I started this project to attempt to determine if the 1919 has been subject to shrinkage over the years. Do any of you have measurements from pre 1925 Buffets?
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Author: John Scorgie
Date: 2004-02-17 05:40
Bill --
There is no standard tool nor standard procedure for measuring clarinet bore diameters, altho the telescoping gage, properly used, is as good as any.
Your description of your measurements indicates that you have some knowledge of tool and die work and thus are already making much better measurements than most players are capable of.
Be wary of published specs in this area. Many are the result of someone merely repeating what he or she was told by someone else, rather than by actual careful measurement of the instrument(s) in question.
In other words, trust your gages and your measurements.
Manufacturers' published bore diameters are the measurements taken at the bottom of the upper joint, altho with a cylindrical bore, such as many of the older clarinets, the top and bottom upper joint measurements should be the same.
The big advantage of the telescoping gage is that you can take measurements at various distances from the end of a joint and (as you have already done) at various points around the circumference of the bore. You can then factor out any anomalous readings. You might want to do some more measurements at various distances from the top end and also from the bottom end just to see how they compare with the measurements you have already done.
Your method of taking readings every 120 degrees around the circumference of the bore is an excellent idea, since with those older horns, concentricity of the bore is typically out by + or - several thousandths. I like to do them every 30 degrees if I have time.
With either a reverse conical or a polycylindrical bore, the bottom upper joint will be smaller in diameter than the top of the upper joint. Altho a cylindrical bore is theoretically the same diameter top and bottom, trust your gages.
Altho I don't have any bore measurements on the really old Buffets, your measurements are consistent with my playing experience on these horns.
Your 1953 model is just prior to the so called R13 vintage (I still have mine -- 51xxx serial # with a slightly smaller bore than yours.) Your serial # should be somewhere in the upper 40xxx. Really nice clarinets.
The older horn is another matter entirely. In the 1950s and 1960s, I was able to blow several ancient Buffets, some of which felt and looked similar to the modern Buffets. Others were quite different, such as a set of full Boehms with donut rings for middle finger L hand and roller keys for the R hand little finger! They were decent clarinets, but all were rather wild sounding compared to the good modern Buffets.
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Author: Don Berger
Date: 2004-02-17 14:28
Excellent question and answer-discussions IMHO, Bill and John. While I "are an "injunier"" [also], its chem not mech tho, and any [recent] machine knowledge I've derived is from watching experts work, and measuring what clar-bores are reachable with my Mitutoyo "caliper" [proper term??]. Well put, re: "egging" of bores over time AND excessive wear at top and botton of the U J and L J. Cant reach into barrels/sockets, dern it! I feel reasonably comfortable, accuracy-wise, when my big-bore horns, Selmers and Leblanc Dyn 2, come out as [close-to] .590" = 15.0 mm. Measuring my Sel-Paris alto and bass cls, and comparing with published specs, revealed [to me] why they play as well as they do. Will be very interested in further discussions. Will look for a "telescoping" gauge, as well. Don
Thanx, Mark, Don
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Author: bill28099
Date: 2004-02-17 17:19
Attachment: guages.jpg (94k)
For those of you that are interested attached is a photo of my set of telescoping guages. Bought on sale at Princess Auto in Canada for less then $30. You can also get ONE of these at a machine shop supply store for about the same price. Extension handles can also be purchased for them.
However, they ARE NOT SUITABLE for contouring an entire bore. They fall in the tone holes and occasionally require clarinet dissassembly to remove. As you can see they also won't work if the entry bore is a smaller diameter then the interior.
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Author: John Morton
Date: 2004-02-17 18:51
A machinist's point of view:
John Scorgie gives a good treatment of the issue. I'll add that a caliper is inappropriate for resolving .001". You are already at a disadvantage having to transfer a measurement from one gauge (the telescope gauge) to another - best to at least use a micrometer. In any case don't use the internal measuring jaws of a caliper, it is nearly impossible to get a true reading. Careful use of telescope gauge and micrometer should get you pretty good measurments - take many readings and use a light touch on the micrometer.
Toolroom practice is to use plug gauges for small cylindrical bores. I should think that for inspecting fairly uniform bores it would be best to have a set of gauges surrounding the nominal size in .0005" increments. (A fairly quick lathe job in aluminum, or you can buy them for a couple of bucks each.)
If the bore is not round, the plug gauge (a simple cylinder) only tells you the diameter of an inscribed circle. The telescope can give you a complete map of everywhere you can reach, but that is only about 3" into the end of a joint. The machinists who do a lot of this type of work like dial bore gauges, which read directly as you move them around but must usually be set to a master reference bore. There is also a type of internal micrometer with three measuring faces at 120 deg., but these should not be used unless one knows the bore is round and not lobed in some way.
Mr. Rod Cameron, a builder of Renaissance flutes, devised a direct-reading bore gauge for measuring flutes in museums. Faced with the problems of oddly varying bores, he came up with a tool that shows the internal diameter on an LED display as it is moved. This has enabled him to make reproductions of complicated geometry with a tracing lathe and home made reamers.
There is better equipment beyond what I have mentioned here, but it's expensive. A clarinetist/researcher would probably take his old instrument to a metrology lab, which would give him a digitized map of the entire bore. This service may be reasonably priced, given the recent advances in automated measurement.
right, this is more than you wanted to know ...
John Morton
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Author: D Dow
Date: 2004-02-17 19:04
I have seen some measurements taken at different times yield different results.
David Dow
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Author: saxlite
Date: 2004-02-17 19:08
I use a nice tapered cylinder plug gauge made by "Sounds Of Woodwinds".
Just plop it in and run the slider down till it stops--then read the diameter marked by the rings every .001". Don't remember where I got it or whether these guys are still in business-but it's accurate and extremely easy to use.
No, you can't have mine!
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Author: Gordon (NZ)
Date: 2004-02-17 20:41
Most clarinets probably develop some ellipticalness in the bore. Such a device would measure only the minor diameter of the ellipse.
What is relevant is cross-sectional area, so taking a set of diameters and averaging at any measuring location would be far more indicative.
Post Edited (2004-02-17 20:43)
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Author: BobD
Date: 2004-02-17 23:20
All very interesting and educational....especially the mention of lobing. Although lobing( at least triangular) probably shouldn't occur in clarinet bores(?) it is an enlightening experience to put a mike or caliper on a tri-lobed "round" bar and find that it measures the same diameter no matter how you rotate it. Personally I take a cavalier attitude about clarinet bore diameter measurements just as I do about "how to do a scored gliss" i.e. does it really matter.
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Author: jbutler ★2017
Date: 2004-02-17 23:40
I use a tool by SPI. I think that John Morton mentioned it. It is called a hole mike. This tool has measures on three faces at one time. I also have a set of pin (plug) gages for quick reference.
jbutler
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Author: bill28099
Date: 2004-02-18 01:22
I'm with BobD, does it really matter? Naaaaa not really, but does let me know why this old Buffet plays a lot like may teacher's Leblanc from the 1950's. However, my initial question has yet to be answered, has the bore of the 1919 Bb shrunk?
I own 4 of these doughnut key Buffets (1904-1922), 3 As and one Bb. The Bb and the 1904 A are fun to play, the 1920 A is a pig and the 1922 A has yet to be worked on.
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Author: Vytas
Date: 2004-02-18 16:48
You don't have to measure to find out if the bore size is correct.
If the total volume (including mouthpiece) of the bore is correct, your clarinet should play very close to 440HZ (or 442HZ) pitch with the barrel pushed all the way in. (@70 degrees F)
If you have to pull the barrel more than 3mm, to play in tune, you have a shrunken bore.
Another indication of dimensional change (shrunken bore) is an excessive gap between the large ring and the body of the bell. The space/gap over 1mm would indicate more than moderate shrinkage.
Many people assume that the bore gets smaller when it shrinks, but that is not what actually happens. Wood shrinks towards the middle. The length basically stays unchanged. The outside diameter gets smaller and the inside diameter gets larger. In other words, the bore gets larger/expands when it shrinks.
Acoustical paradox:
If you increase total volume of the bore by increasing the total length of the instrument, your clarinet will play flatter.
If you increase total volume of the bore WITHOUT increasing the total length of the instrument, your clarinet will play sharper.
Your instrument will play sharp through entire range with a shrunken/larger bore.
Barrel length for a 1919 Buffet is 68mm-69mm.
Vytas Krass
Pro clarinet technician.
Custom clarinet mouthpiece maker.
Former pro clarinet player.
Post Edited (2004-02-18 17:17)
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Author: Hank Lehrer
Date: 2004-02-18 20:03
Hi,
John Morton said "In any case don't use the internal measuring jaws of a caliper, it is nearly impossible to get a true reading." I'm sure this is absolutley correct in the empirical sense but in the practical sense (not an engineer or toolmaker) to give me a "ball park" idea of the bore, I have used the internal caliper for that measurement.
I know I am giving up accuracy but at least I have an idea of what's what (and I have a digital caliper available).
HRL
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Author: John Scorgie
Date: 2004-02-18 20:36
John Morton --
Thanks for your most informative post, which is definitely NOT more than I wanted to know about the subject, since I never had any formal training from a machinist. All of my limited knowledge in this area has come through trial and error.
Since we are on the subject of bore diameters, for your encore, would you consider giving us another "machinist's point of view", this time as to the probable reason that Buffet changed from a "reverse conical" bore to a "polycylindrical" bore back in the 1950s?
I am hoping that your take on the matter will either shore up or shoot down my suspicion that the change was made for production reasons, and that the particular acoustical advantages of this bore configuration only came to light some time after the initial retooling and change in production process.
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Author: BobD
Date: 2004-02-18 22:14
JohnS: Trial and error is at the root of it....that's why it's not "trial and success'. We only learn when we make errors. There's nothing wrong with using a dial caliper for ball parking ....it's when you are machining a part that it's iffy.
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Author: bill28099
Date: 2004-02-19 03:12
Thanks Vytas for your comments and putting this problem in perspective. The barrel of this 1919 Bb is 67.5 mm. Given there are pretty much equal numbers of sharp/flat/intune notes I must assume that the instrument has not significantly shrunk. Unfortunately my pitch meter does not give an absolute reading, just whether a note is sharp/flat/intune. I did have to have all the rings tightened but the bell was kinda mangled so really have no idea how loose its rings were.
I do own a set of outside micrometers and do use them when accuracy is a must. It's just that the digital caliphers are so much easier for old eyes to read.
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Author: John Morton
Date: 2004-02-19 16:12
Hank, I do subscribe to your philosophy of using what you have. What really matters is that you are aware of the limits of the tool. I use only a dial caliper (rather than a digital - they cost the same) for just this reason. Measure a bore with a dial caliper and you will see the needle move as you make tiny changes in your hand position. That range of motion could be used as a tolerance on your measurement because it represents uncertainty.
Digital measuring tools are notorious for two reasons: 1. you don't see the analog of the reading as it rises and falls (a bit like a speedometer needle versus a display with shifting digits); and 2. you are tempted to believe that the counter shows significant figures. A reading of ".5903" is very persuasive, but when you see the distance between the .001" graduations on a dial you realize that splitting thousandths is an absurdity.
Another issue with calipers is that the inside jaws must have flat measuring surfaces. Therefore you are really measuring between chords of the circle, introducing an error (on the low side) which changes with the diameter. And yet another: the jaws are squeezed as the measurement is made. Squeeze a little harder and you get a different reading. This is why a micrometer is so beefy and has a friction thimble for applying the same pressure every time.
I wouldn't mention any of this except that small tolerances are routinely claimed for bore measurements, e.g. the taper in Moenig barrels.
Re: John's thoughts about bore configurations ... I don't know Buffet's definition of "polycylindrical", but I suppose it means cylindrical bore sections of different diameters. Cylindrical bores are vastly easier to control in production, because they require only reamers of the correct size, which can be run right through a tube. Tapered or conical bores require tapered reamers which must be brought to an exact axial position, then retracted.
Disclaimer: I won't claim to know anything about woodwind manufacture, and it would not surprise me to learn that there are tricks that have been used for centuries that we machinists know nothing about!
John Morton
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Author: bill28099
Date: 2004-02-19 18:19
Attachment: image007.gif (7k)
Attachment: image008.gif (7k)
Re: polycylindrical
Some time ago I found the following two graphs on the web, maybe even on this site. I always thought they were kind of interesting but wish I knew the clarinet's serial number..
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Author: John Scorgie
Date: 2004-02-19 20:09
John Morton --
The difference between working with cylindrical and tapered reamers which you note in your penultimate paragraph is exactly what I was talking about in reference to the R13 bore.
Thanks also for pointing out that in reference to bore diameters, "splitting thousandths is an absurdity".
I find that this statement is equally applicable to published specs for mouthpiece tip openings. That large French manufacturer which specs its tip openings as "1.195 mm" or "1.065 mm" is perhaps the worst offender in this regard. My experience with actual measurements suggests that this firm should chop off one decimal place from its published specs and then add "+ or - 0.05 mm" to the specs which remain.
Flamers, please note that I am not knocking the products of that company. I have owned and played several mpces and many hundreds of reeds from that company over the years, and have the greatest respect for both. But I maintain that their specs are strictly science fiction and that most samples of these products can be improved through final adjustment by a capable hand.
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Author: Don Berger
Date: 2004-02-23 21:51
I found this thread very educational, and the comments by expert engr-machinists have pointed out measuring problems/methods clearly. In pursuing some patent searching on cl bores, I found 2 US patents to Lorenzini of possible interest to some of us: Gauge --Internal Diameter #4,219,937, and Mouthpiece Facing Gauge#4,485,559. They are in US Pat Class 33, Measuring. Read 'em if interested, Don
Thanx, Mark, Don
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Author: John Morton
Date: 2004-02-23 22:58
re: bore measuring devices, a builder of shakuhachi flutes has been using the methods I mentioned which were devised by Rod Cameron:
http://www.shakuhachi.com/Q-PCBStory.html
The photo shows that the map of the bore is plotted on a strip chart. The page also refers to Rod's "laser tracker" for cutting mandrels and reamers to the plotted shapes. This is an absurdly simple system, a testimonial to an inventive mind.
A plot of the profile is taped to the wall behind the lathe. A laser attached to the toolpost points down at a little mirror on the lathe apron, which reflects a dot onto the wall, such that a movement of .001" in the tool position results in a movement of perhaps .1" at the plotted line. As the tool feeds longitudinally, the operator has merely to keep the laser dot on the line, using the crossfeed handle.
John Morton
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Author: Hank Lehrer
Date: 2004-02-24 03:29
Hi,
The comment "This is an absurdly simple system, a testimonial to an inventive mind" is so right on. And a laser, of course.
I was a JPL in Pasadena a few years ago visiting a students doing a summer internship and I just happened to be out in the parking lot when they tested the rover prototype (yes, the one that actually went to Mars). They used a laser and a prism to send the code and from one end of the parking lot to the other, I saw teh rover stop, turn-around, and then move back. Everyone went crazy as this was a huge breakthrough. You never know when you are going witness history in the making. They were also working on climbing using deep sea fishing reels. All of these items were off-the-shelf materials. The inventive mind again and an absurdly simple system!!!
I have really enjoyed this thread and the fact that we need to remember that sometimes the Law of Parsimony is absolutely correct.
HRL
PS Loved the bore diagrams.
Post Edited (2004-02-24 13:43)
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Author: BobD
Date: 2004-02-24 16:14
The shakahuchi reference of John's above is very interesting and certainly must have some relevance to how important precise bores are to clarinet performance. My impression of Buffet's "polycylindrical" term is that it is a bore produced by a tapered reamer(s) or equivalent methodology.
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Author: Don Berger
Date: 2004-02-24 18:29
Thank you, John Morton, for bringing the shakuhachi flute to our attention, what an informative publication ! I consider it to be a good day when contacting new information ! I then looked up in Curt Sachs "History --- Musical Instruments", on pg 213 he discusses in a paragraph the shaku - hachi vertical bamboo flute, of 4 + h [?] finger holes, as "mellowest" and "exceedingly" difficult to play. A patent [quite unrelated] refers to it as a 5 tonehole bamboo !clarinet! All in all, this is prob. new info to most of us on the BBoard. TKS, John , Don
Thanx, Mark, Don
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