 The Clarinet BBoard
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Author: Fuzzy
Date: 2018-04-06 03:54
So, a couple years ago, I was hooked up with a wonderful old hard rubber B&H Albert System bass clarinet. Life got terribly hectic, and I never finished repadding the instrument and getting it into top playing condition.
I'm trying to remedy that at this time. However, as I began to disassemble the instrument, it has become obvious that the rod screws have been heavily used over the years (by folks disassembling the instrument and such). Many of the screw heads are 90 percent "slot" and 10 percent metal. Meaning: The head of each screw is nearly worn out - some only have about .5 mm of slot depth, or are missing a side of the head's "slot". I gotta hand it to the previous owner, though - he kept all the rods oiled wonderfully, and all the screws come out just fine. However, a couple screws come out "too easily" - as in - the threads don't catch at all.
Using magnification, I can see at least the markings of threads in the post, but the screw just slides in and out. I'm not sure if the rod is simply cut/threaded incorrectly, or whether the posts have been stripped too far to accept a normal thread.
I don't have my own set of taps/dies, nor any rod stock. I'm unaware of any reputable repair folk in my area and wonder how I might figure out exactly what I might need to order (Like, if I could give dimensions to a repair person, who could then mail me the rod screws?) Or whether anyone has recommendations for a quality repair person in the Denver, Grand Junction, Salt Lake, Casper, etc. areas. (Anything in the Utah, Colorado, Wyoming, or western Nebraska areas?)
I own a standard (non-metric) set of calipers which go down to the thousandth of an inch, but I'm not sure if that would be good enough, or how I might determine the correct thread size/type/count. So, I think it would be best for me to take the instrument to someone.
Any thoughts or recommendations would be greatly appreciated. I'm hoping not to mail the instrument off, as we have terrible luck with shipping in this area.
Thanks!
Fuzzy
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Author: clarnibass
Date: 2018-04-06 10:54
I don't know from memory if B&H could be either imperial or metric or if they have always used one type.
If your calipers are accurate, then 0.001" is good enough to check the thread diameter of the screws... if it's not too worn... keep in mind they are usually slightly under size from manufacturing and some companies use very non-standard sizes sometimes.
It might be worth getting metric and imperial thread gauges. Good to have anyway unless you really only need it for this one instrument.
The diameter of the rods themselves is hard to do by measuring, too many variables. The regular method is to check one, then check a size larger or smaller depending on the fit, but of course this requires a stock of sizes.
Check several screws in various posts. That way you can often tell if some screws are too worn or if only some posts are worn. Even though posts are usually brass or nickel-silver and screws are usually steel, sometimes the screws wear and not the posts.
If the fit of the current rods is good, then it might be possible to do this by measuring, but you have to use something far more accurate than 0.001" calipers. Good digital calipers is the least accurate I would use, preferring a micrometer. Even then, if you order doesn't mean it's the same as specified, there are tolerances, etc. If it ends up 0.01mm too large it might not fit. If you went with something slightly smaller to be safe and then it's a tiny bit smaller, now it's too loose.
After you check the thread diameter it will give a pretty good idea of possible thread sizes. If you can have a really magnified photo of the threads next to a known length (e.g. your calipers open to exactly 5mm) then it might be possible to get pretty close to the right sizes. I've found the thread for a couple of people before this way when they didn't have good measuring tools and were on a different continent
Getting the thread gauge would be better
I know a repairer who is supposed to be reputable in Utah, I think he is in Springville. If that might help I can email you his contact details.
Post Edited (2018-04-06 15:03)
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Author: Chris P
Date: 2018-04-06 19:04
The more recent B&H clarinets used mostly 2.2mm diameter rod screws with an M2x0.4 thread (or the imperial equivalent).
If you're replacing all the rods, then you can use whatever diameter steel for them and the thread size of your choice if it's similar so they all have the same diameter and threaded screws for consistency.
The problem with some antique clarinets is the rod screws often had a wider diameter head, so in that case it's probably better to bush and redrill all the pillars to accept completely parallel-sided rod screws.
As both screws and key barrels will be worn, you're best going oversize and also buying or making a reamer to ream all the key barrels (and pillar heads) to the new diameter. Key barrels can be swaged to fit the rods so they won't wobble, but worn out pillar heads will be a problem as you want the screws to be a tight fit in the pillars for reliability.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Fuzzy
Date: 2018-04-07 05:17
Thank you all for the varied responses!
Clarnibass - as always, you've provided great information. Hopefully, I'll be able to find someone to do the work for me, but if not - you've given me a great start on what I might be able to do in measuring/buying. I do see a tech in Springfield listed on the link Steven provided...perhaps it is the same person you were thinking of? Either way, I'd be happy to receive an e-mail from you pertaining to this issue.
Chris P - if it wouldn't take me a couple years to plan/schedule/save for it - I'd hop a plane and drop it off with you (along with another project instrument I'd love to have you work on) while I proceeded on to Sark. Sadly, that's not in my cards right now. I love hearing your take on stuff and it would be exciting to see the results of what you've recommended!
Steven - Thanks for the link! I'm a little uncertain how much faith to put in the tech search results. I notice that the requirements for membership aren't necessarily definitive (meaning - they specify a minimum experience which could result in quite a varied skill set.) I'll probably start calling folks from the list this weekend and next week to try to find a specially skilled person, but I'd still be greatly comforted if anyone here might be able to recommend a specific repair person.
I took a saxophone down to a well-reputed saxophone shop down in Colorado a few years ago, only to waste two days in travel, nearly a month waiting, and received a result that was equal to something I could have done the afternoon I discovered the problem to begin with. Between the cost and the results, it is a situation I would like to avoid repeating. Plus, this time, I'm dealing with a clarinet that has special meaning to me. ;^)>>>
Thanks again - I'll be keeping an eye on this thread in case anyone provides further advice, and I'll be sure to post back if/when I find someone or run into further questions while trying to winnow the field!
You folks are the best!
Fuzzy
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