 The Clarinet BBoard
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Author: Tony F
Date: 2023-05-12 17:09
I'm in the process of repadding and restoring an elderly 1010. One of the rods on the upper joint has a stripped thread in the post. Does anybody know what thread B&H used on these rods?
Thanks,
Tony F.
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Author: Chris P
Date: 2023-05-12 22:35
It's either an 8BA or 9BA (I'm thinking more towards 8BA), although an M2x0.4 will work.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Tony F
Date: 2023-05-13 08:46
Many thanks, Chris. You are a mine of information.
Tony F.
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Author: Chris P
Date: 2023-05-15 01:32
I just checked a 9BA tap and that ran through a B&H pillar thread no problem (an early '50s ebonite Edgware with rod screws throughout), so it's definitely 9BA threads they used.
Back in 2001 I used B&H rod screws when I completely rebuilt my old CT A clarinet as the 'repairer' I naively trusted to rebuild it back in the early '90s reamed all the key barrels out to 2.2mm, then bunged in 2mm rod screws so everything was ridiculously sloppy. I tapped all the pillars on that CT out with an M2x0.4 tap and the B&H screws with 9BA threads fitted them fine, although an M2x0.4 screw thread will bind up in a pillar tapped out with a 9BA thread.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Tony F
Date: 2023-05-15 18:02
Thank you, Chris. You have almost exactly described my problem here, although mine is only present on one rod and post. Sometime in the past when the thread went in the post whoever was working on it made the thread work again by removing the post and hammering the hole oval. Many years and possibly several owners later, when I removed the rod it left most of what remained of its thread in the post. Fortunately I have in my junk box an old 926 top joint which uses the same post, so the only problem remaining is the rod. Knowing the thread I can now see a light at the end of the tunnel. Mind you, it could be a train coming the other way.
Tony F.
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Author: Chris P
Date: 2023-05-17 01:41
The worst thing to be faced with is bodged up attempts at previous quick fix repairs when someone's done something like this. What would normally be a straightforward job for someone with all the right parts that should go straight on ends up turning into major surgery when you're having to source, adapt or even fabricate new parts.
This is why I went into woodwind repair as I lost faith in the repairers in my area who may have all the qualifications and training, but chose to take shortcuts and took no pride in what they did judging by the results, yet they still feel the need to criticise my work.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
Post Edited (2023-05-17 01:41)
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Author: clarnibass
Date: 2023-05-17 09:04
>> One of the rods on the upper joint has a stripped thread in the post. <<
>> so the only problem remaining is the rod. <<
Did you check it in the new post? What is the problem with it? Do you know what thread it has now? If the rod itself (unthreaded part) is fine, and the threads aren't too small (which I assume they aren't since the post was enlarged to fit) it might be as simple as running it through a 9BA die.
If the threads fit other than size then as Chris mentioned, M2x0.4mm is most likely. The difference of 0.40mm vs. 0.39mm for 9BA is insignificant for woodwind key threads.
Woodwind threads are usually on the small size. It's not uncommon for M2 to be almost M1.9, which happens to be the diameter of 9BA threads. Posts are a fraction oversized too. It might be that it was barely binding slightly and they enlarged the post more than it was even needed... something like that.
Even though the angle is different and it's not ideal, an adjustable M2x0.4mm die is likely adjustable enough to work, and could be much easier to find than 9BA (at least here, depends where you are I guess). Another good option is 1-64 UNC. Threads are also essentially the same and nominal diameter is 1.85mm, preferably slightly adjusted.
Just throwing some alternative solutions in case the ideal one isn't available...
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Author: Tony F
Date: 2023-05-17 18:05
Hi Nitai,
Thanks for some useful info. The post concerned is the bottom post on the upper joint, the double stacked on. The damage was to the upper threaded hole, which had been hammered oval at some point in the past. The thread on the rod was pretty well shot as well, but as I mentioned I had in my junkbox a top joint from a 926 Imperial, which is identical. I have successfully fitted it and there were no problems with alignment. I had some long ex-926 rods as well, so I cut one down to replace the damaged rod. All is now well and it plays better than ever. I shall expand my collection of dies.
Tony F.
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