 The Clarinet BBoard
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Author: Reformed
Date: 2026-04-25 20:12
It is common for most wooden clarinets for the bore at the top of the upper joint to expand over use and time.
I have a grenadilla 1010 which has expanded from the cylindrical 15.24mm to 15.50mm.
I also have an ebonite 1010 which is still at 15.24m, probably because the tens are sleeved.
One noticeable effect of this is that the expanded bore instrument has a very wide F/C 12th, the C at the top of the staff is quite sharp. Whereas the ebonite instrument is in tune.
What is the best way to fix this?
I was thinking of a DIY approach through building up layers of a coating and eventually finishing off with a reamer to the right specification.
This raises the question of what coating to use:
- There are "food safe" lacquers but I doubt their durability,
- 2 pot epoxy varnishes would probably work well (e.g. in the UK - Rustins Plastic Coating), but are almost certainly highly toxic even when set
- A liquid shellac would probably also work but finish up being quite brittle
A custom metal sleeve would also work but I am not sure if anyone would take this on.
In my student days, I remember seeing a fellow students Austrian regular Boehm clarinet (not Reform) where the bore was quite deeply lacquered (from one of the Hammerschmidt brothers maybe?) but have no idea what lacquer was used. There were some small chips around the bore ends.
Any comments welcome!
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Author: donald
Date: 2026-04-26 03:17
I'm sure I recall there was a company in Europe (with a USA branch) that would "re sleeve" the top joint of your clarinet. The reason your ebonite clarinet still has the same measurements is because it's ebonite and the bore doesn't absorb moisture so doesn't warp/expand/go oval over time.
There is a theory that swabbing wears the bore "open" over time, but most people involved with actually making wind instruments out of wood laugh at this.
Some makers of "Irish folk flutes" and various pipes (Aeolian pipes etc) do what is called "cast bore" where they make the instrument, then either fill the inside with a laquer substance which they then remove by reboring (more work, better accuracy with dimensions) OR just cover the bore with a thin layer (cheaper, quicker but dimensions not as accurate).
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Author: donald
Date: 2026-04-26 15:35
Yes, they do very very good work, and I've only heard good reports about their bore restoring, however their theory that the enlargement is caused by swabs is generally regarded as a bit silly (just one counter argument, the frequently encountered example of cotton swabs leaving lint in tone holes is evidence that the swab is LESS abrasive than the bore) and generally ignored by most people who actually work making instruments (and have the most relevant experience).
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Author: A Brady
Date: 2026-05-02 19:51
This has been discussed quite a bit in previous posts.
Guy Chadash replaced the bore in my 1967 R13 B flat, and also in my 1974 R13 A. Both had been played a lot by that point, and the focus and intonation were suffering.
http://test.woodwind.org/clarinet/BBoard/read.html?f=1&i=361922&t=361893
The procedure worked wonderfully, and both continue to play very well, after having the procedure done in 2007 and 2008.
Guy is in NYC, close to the Port Authority Terminal. I haven’t seen him in a few years, but I’m sure he still offers this service. I don’t know what he currently charges.
Worth a try for an older instrument that isn’t playing like it used to.
AB
Post Edited (2026-05-02 19:53)
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