 The Clarinet BBoard
|
Author: SteveG_CT
Date: 2011-08-25 05:24
Here's a question for the techs out there: A while back I acquired an NOS bell for one of my clarinets with the intention of replacing the original bell that is cracked in a few places. The new bell is identical except that the tenon socket is smaller in diameter by about .040" and as a result it won't fit on the instrument. The tenon on the lower joint is pretty thin already so I think it would be best to remove material from the socket rather than the tenon. Is there an elegant way to do this other than slowly by hand with a piece of sandpaper?
I thought about doing it on my lathe but I don't really have a good way to securely hold the bell so this would likely end in disaster.
|
|
Reply To Message
|
|
Author: BobD
Date: 2011-08-25 11:18
I'm not really a "tech" but I've worked on a lot of clarinets. I guess the first question I have is WHY the original bell has cracks....and are any of them in the socket area. The second is....is it wood or plastic. Regardless of material, reducing the wall thickness of the socket is a risky solution......and doing the same on the tenon is even riskier. One possibility: Go ahead and open up the socket and then reinforce the outside of the socket area with carbon fibre. To open the socket on the lathe make a fixture to go inside the bell, stopping short at the socket...lots of work. Conclusion: Get a bell that fits as-is.......or fix the cracks in the original.
Bob Draznik
|
|
Reply To Message
|
|
Author: SteveG_CT
Date: 2011-08-25 13:46
Bob,
The original bell was damaged during shipping and has some cracks down the side but not in the area of the socket. On the "new" bell (actually made in the early 1950's) the wood in the socket is noticeably thicker. I speculate that this may have been done on purpose so that it could be custom fitted on any instrument needing a replacement.
|
|
Reply To Message
|
|
Author: David Spiegelthal ★2017
Date: 2011-08-25 16:09
Dremel tool, sanding drum attachment, go around inside the bell tenon socket, will take about a minute to remove enough material to fit your bell. Check frequently as it doesn't take much time. Save the wood dust for future hole patching/crack repairs (mix with epoxy for those).
|
|
Reply To Message
|
|
Author: rtmyth
Date: 2011-08-25 18:01
Remove some cork gasget with 600 grit paper. Grease gasget; try now. If not enough, use 600 grit paper or cloth to remove some of bell inner bore. ( I would first check all dimensions with a calliper; then proceed with caution.)
richard smith
|
|
Reply To Message
|
|
Author: SteveG_CT
Date: 2011-08-25 18:08
Richard,
I wish it were as simple as just removing some of the cork but in this case some wood will need to be removed. I was hoping that someone would know of a tool for doing this while maintaining concentricity but it appears that I will have to do it by hand. I guess I'll just work it slowly with emery cloth and do my best to keep the socket the proper shape.
|
|
Reply To Message
|
|
Author: Caroline Smale
Date: 2011-08-25 19:01
If you have a friendly auto tech with an expandable reamer covering the correct range (about 26.5mm) this could be carefully used to gradually open the socket and would ensure reasonable roundness / concentricity. But stop well short of the very inner end of socket and finish this area by careful dremel work and hand scraping.
|
|
Reply To Message
|
|
Author: rtmyth
Date: 2011-08-25 20:01
Me, again. On one of my used TR147s I had to remove some of the inner bore of the bell. I did it by hand; roatating the bell with one hand while holding, with the other hand, a piece of paper grit against the inner bore. I started with 400 grit and finished with 600, using a digital caliper frequently.It worked well. The material was hard rubber , but should work for wood too..
richard smith
|
|
Reply To Message
|
|
Author: BobD
Date: 2011-08-25 21:15
Sockets are not always concentric or perfectly round.......
Bob Draznik
|
|
Reply To Message
|
|
Author: BobD
Date: 2011-08-25 21:22
I just have a real hang up about removing wood from the socket of a conventional bell......Sure, you might get it to fit......once.....twice but then what.....shrinkage, a loose ring and crack.......
Bob Draznik
|
|
Reply To Message
|
|
Author: Chris P
Date: 2011-08-25 23:52
If it's a Selmer CT or Series 9, there isn't much thickness of both the bell socket and lower joint tenon that can be removed without further weakening them.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
|
|
Reply To Message
|
|
Author: Ken Shaw ★2017
Date: 2011-08-26 00:49
I watched one tech enlarge a barrel tenon socket using a curved wood chisel about the diameter of the socket interior. It seemed like a trial-and-error process, though.
Ken Shaw
|
|
Reply To Message
|
|
Author: SteveG_CT
Date: 2011-08-26 05:49
Attachment: Original_Selmer_CT_Bell.jpg (62k)
Attachment: NOS_Selmer_CT_Bell.jpg (51k)
Chris P wrote:
> If it's a Selmer CT or Series 9, there isn't much thickness of
> both the bell socket and lower joint tenon that can be removed
> without further weakening them.
>
In fact this is a bell for a Selmer CT. The wood is quite thin around the socket of the original and quite a bit thicker in the same area on the new bell. I have attached some pictures for clarification.
|
|
Reply To Message
|
|
Author: Chris P
Date: 2011-08-26 08:27
There's enough to work with there, but still go easy when removing it.
Can you turn your lathe chuck jaws around so it grips the lower bell ring? That would be the best way to hold the bell (and centering the socket - probably best using a three jaw steady as well) so you can open up the socket. Or isn't your lathe large enough?
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
|
|
Reply To Message
|
|
Author: RefacerMan
Date: 2011-08-26 12:37
Whenever I need to enlarge a socket and keep it concentric and parallel I use the tenon of a mouthpiece. I find the correct mouthpiece to fit into the socket and then carefully wrap masking tape on the tenon of the mouthpiece to get it to a little under the size of the socket I want to enlarge. Then I tape a piece of sandpaper to the masked tenon and use that inside the socket turning it by hand to sand it larger. As the socket gets larger I wrap a little more masking tape around the mouthpiece tenon to enlarge it. This is a good way to keep the socket "square" and concentric.
|
|
Reply To Message
|
|
Author: BobD
Date: 2011-08-26 15:11
Sounds like a decent approach RefacerMan.....for barrels.
Bob Draznik
|
|
Reply To Message
|
|
Author: SteveG_CT
Date: 2011-08-26 15:59
Chris,
My lathe is more than large enough (I have an 11" Logan) but I have some concerns about trying to grip the bell by a surface as narrow as the bell ring without inadvertently damaging it. I agree that using the lathe and a boring bar is the best way to open up the socket as this is likely how the work is done at the factory.
I may try mounting one of my old junk bells on the lathe and see if I can accomplish this without damaging it.
|
|
Reply To Message
|
|
Author: Chris P
Date: 2011-08-26 16:33
As the bell ring is unplated, if it does get scuffed or marked by the chuck jaws, it isn't a huge problem to tidy them up. But wrap something tough around the bell ring to protect it in any case.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
|
|
Reply To Message
|
|
The Clarinet Pages
|
 |
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
