 The Clarinet BBoard
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Author: nron
Date: 2016-03-14 16:33
Hello BBoard
I would like to find out if anyone has had any experience or has any ideas about a problem I'm having.
The rod crew on my upper joint key stack keeps working its way lose and unchecked, the stack falls off whilst playing which happened to me. I find that I have to check that screw often and just tighten it up occasional - really just a bother than a problem.
A rod screw keeps coming lose on my flute as well and the same thing was happening on my saxophone. However on the sax I eventually cranked the screw shut and no problems but i can't do this on the others because the keys will not lift if the screw is too tight.
My thoughts are that because I have been driving recently, rather than taking public transport, motor vibrations have worked the screws lose (I also drive a diesel car - maybe these vibrate more?)
if anyone has any ideas about whats going on that would be great or quick home fixes too
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Author: Chris P
Date: 2016-03-14 16:54
This rod screw is effectively a long point screw, so the end of the LH2 ring key barrel will need to be countersunk for the point to fit properly when the rod screw is fully tightened into the pillar. A lot of makers leave this rod screw loose so it can be adjusted, but it all too often works its way out over time as you use the thumb ring and LH1 ring key.
Screw threads need some form of resistance in order for them to stay put and this is usually done by having the shoulder above the screw thread engage squarely with the face of the pillar. If it has a nylon lock on it (either set into a slot on the thread or a collar like Buffet point screws), then it can be adjusted to a good fit, but not all screws with nylon locks are reliable.
So have the screw fitted properly so it is tight in the pillar like the other rod screws and also making sure the LH2 ring key is also a good fit between points so it has no lateral play but still moves freely. The point screw at the lower end of the LH2 ring key can be used to adjust the fit, but it too should ideally be a tight fit in its pillar.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Steven Ocone
Date: 2016-03-14 16:54
A repair tech can modify the screw so that it can be screwed in all the way without binding any keys.
Steve Ocone
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Author: kdk ★2017
Date: 2016-03-14 17:06
This is a perennial problem with a lot of my students' clarinets. The ultimate solution is to tighten the screw hard enough that it doesn't work back out. But, as you've described, most of the time tightening the screw that much binds the key. The screw is binding somewhere inside the key barrel and is turning slightly with the motion of the key. The same thing can happen with pivot screws.
The best fix is to have a skilled repairer fit the screw properly in the barrel so that it doesn't move when the key barrel turns and doesn't bind the inside of the barrel when tightened down firmly. Not ordinarily a DIY job - not difficult but takes some skill and experience to avoid making things worse.
The alternatives are to leave the screw slightly loose and check it regularly, as you're doing, except more often so the key stack doesn't fall off., or tightening as much as possible without binding the key and dabbing a little nail polish over the end of the screw to try to keep it from moving.
In any case the screw should be adequately lubricated.
I would always prefer to have the screw fit properly and the key fully tightened.
Karl
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Author: clarnibass
Date: 2016-03-14 19:44
As others mentioned the best solution is to have the screw and key repaired so it can be tightened firmly all the way and the key doesn't bind. Almost always a screw comes out because it's not tightened enough.
>> The alternatives are to leave the screw slightly loose and check it regularly <<
An alternative to that is to have the threads hold better even if it's not tightened all the way. There are a few ways to do this.
One is Loctite, but it is trickier than regular pivot screws.
Remove the D/A ring key and its pivot screw (opposite of the long rod/pivot screw). Clean the F# key and posts. Oil the F# ring key (and rod if you want) and mount it back on. Loctite can be pretty resistant to oil but there's a chance this is less reliable. Some Loctite is specific to resist oil, but not sure the weak type is one of those. Tighten the crew about as much as is ok without binding (guesstimating). Wipe any extra Loctite that oozes out of the post on the pivot screw. Oil/grease the ends of the D/A key and assemble it. Adjust so the screw there's no binding and no (or a minuscule amount of) play.
You can also clean all parts and assemble dry with Loctite the same way. Then oil. Even "medium" thickness oil would eventually get into the key, even if it doesn't seem like there's any play at all.
Either way make sure there's no Loctite on the sides of the post before assembling.
An even faster and "cheaper" method is to "ruin" the threads so they have more resistance. This can actually be an excellent way especially when an instrument is barely worth repairing, but I don't really recommend it because someone can easily cause too much damage.
In reality other than an emergency or extremely low budget (charity...) repair I'd do the first method of fitting the keys, but they are options when that's not a possibility.
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Author: Paul Aviles
Date: 2016-03-14 20:52
Ok, as long as you guys are oiling your keys once every month, I can see myself agreeing with some of the fixes above. I have to say though, with a regularly oiled rods and pivots I have never had an issue with either backing out.
I would advise against Loctite. That seems like a pretty extreme fix for a simple problem. Backing out is symptomatic of the binding occurring along the points where the key needs to move freely around the rod or pivot.
..............Paul Aviles
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Author: clarnibass
Date: 2016-03-14 21:14
>> I have to say though, with a regularly oiled rods and pivots I have never had an issue with either backing out. <<
Were any of those not tightened all the way because if they were they caused binding?
>> I would advise against Loctite. That seems like a pretty extreme fix <<
Just the opposite. It's not a real repair I would do when repairing a clarinet, but a quick, completely reversible, easy way to fix the problem. Nothing extreme about it at all.
>> Backing out is symptomatic of the binding occurring along the points where the key needs to move freely around the rod or pivot. <<
Sometimes. In the case of the OP, he specifically said he purposely leaves the screw not tightened because otherwise it binds the other key. If the threads are not tight (and they often aren't) then there's more friction between this long screw and hinge than anywhere else. If the screw is not tightened then it makes sense that it moves with the key (even if oiled). It also makes sense that it screws itself out and not in, since this is the direction that will remove friction from the threads instead of adding more friction.
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Author: Matt74
Date: 2016-03-14 21:44
Attachment: pivot screws.jpg (3k)
Attachment: screw in post.jpg (3k)
Locktite is a good solution.
There are basically two kinds of pivot screws; ones with heads and ones without. It sounds like you have one without.
The ones without heads never tighten, they're not meant to. They adjust precisely to the right distance to just allow the key to turn freely. Yours may be loose in the post, the key might be out of alignment, or there might be some crud where it turns in the key that is causing it to come out.
The ones with heads USUALLY tighten. They're usually meant to tighten all the way, but may not in a given situation. The purpose of the head is to tighten onto a relief in the post. They are not adjustable. You have to ream out the relief in the post to make them tighten further.
See the attached images...
Screws WITH HEADS work the same whether they are barrel shaped, pointed, or barrel and pointed.
- Matthew Simington
Post Edited (2016-03-14 21:56)
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Author: Chris P
Date: 2016-03-14 23:05
A rod screw with a point at one end is effectively a point screw with a head - the head being the rod itself on which the hollow LH1 ring key (or fingerplate) barrel pivots on in the case of both flutes and clarinets, so they should be treated as point screws with heads as that's exactly what they are, albeit a rather elongated head in the form of the rod itself.
The cure here is simple - as it's the LH2 ring key that's binding when this screw is tightened, the upper end of the key rod will need to be countersunk until a perfect fit is achieved, so not something anyone should attempt unless they have the skill and proper tools for this job as it doesn't take much to go from a binding fit to a very sloppy fit if too much metal is removed.
Countersinking solid key rods (or floating steels as on oboes and flutes) involves removing an absolutely tiny amount of metal, then checking the fit and removing just the right amount for the ley barrel to move both freely but at the same time have as little lateral play as possible (but more with plastic bodied instruments due to the instability of plastic under varying temperature conditions).
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Paul Aviles
Date: 2016-03-15 00:17
Dear Clarnibass,
So, I see what you are saying with regard to the OP's post about the rod/pivot for the LH rings. However I have personally not had a problem when I don't tighten this down. As long as the threads of the pivot are mostly engaged, the axle should not move with the key (as I say, mine never do). I had an issue with the very top pivot on my Wurlitzers and chose to tie some thread around the base of the head to provide "packing material" and that worked fine.
Of course the other way around the OP's issue may be simply to slightly loosen the pivot at the bottom while tightening down the top rod/pivot (if that juggling act works). And for added confidence that the lower pivot won't fall out (and get lost), he could try the "packing material" idea to give it some grab.
I don't like Loctite because it is rather foreign to the whole system. I'd rather keep it to the provided materials and lubricant alone. Just my preference.
...............Paul Aviles
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Author: clarnibass
Date: 2016-03-15 10:10
>> I don't like Loctite because it is rather foreign to the whole system. I'd rather keep it to the provided materials and lubricant alone. <<
It's not. Sorry but this is not a good reason. It's just newer but not really new. You know who else suggests Loctite... a woodwind pivot screw manufacturer. Do you object to those screws with plastic sleeves, or any synthetic materials on a clarinet? OTOH you suggest packing material... Sorry if it sounds rude, I just rather others reading this not getting the wrong impression of (weak) Loctite. If someone assess it by the actual physical way that it works they can tell there's no problem with (weak) Loctite. That said, it's still not the way I would use to actually repair this problem (best repair is what Chris and Steve wrote above).
>> However I have personally not had a problem when I don't tighten this down. As long as the threads of the pivot are mostly engaged, the axle should not move with the key <<
You haven't but many other clarinets don't have enough friction in the threads themselves to prevent this.
>> Of course the other way around the OP's issue may be simply to slightly loosen the pivot at the bottom while tightening down the top rod/pivot (if that juggling act works). And for added confidence that the lower pivot won't fall out (and get lost), he could try the "packing material" idea to give it some grab. <<
Weak Loctite is excellent for preventing loose pivot screws from falling out. It's one of the best methods.
If tightening the top rod/pivot screw causes binding, it's entirely possible it pushes the key against the lower post, not only the pivot screw, and in this case loosening the bottom screw won't help.
So this is the other way around it sometimes, but not always.
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Author: Clarineteer
Date: 2016-03-15 11:02
Clarinet parts houses such as Votaw sell threadlocker made specifically for this purpose.
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Author: Paul Aviles
Date: 2016-03-16 02:02
I guess I am leery about giving someone (anyone) the excuse not to regularly lubricate because "the pivots/rods are not backing out."
If you are saying that you just Loctite every month with your regular key oiling, then I suppose that is fine (I still personally won't use it).
................Paul Aviles
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Author: kdk ★2017
Date: 2016-03-16 17:05
Just to ground this discussion of adhesives, they are really quick fixes - palliative first-aid that people use mostly to avoid a trip to a repair shop. Whether to save time or money, you're band-aiding the real problem, which is ill-fitting hardware. No clarinet is designed so that the screws are meant to back out when the keys are moved.
The permanent fix is to have a repair tech do whatever reaming, countersinking or other tinkering is needed to allow the screw to be tightened down enough that it doesn't move when it shouldn't.
Karl
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Author: Matt74
Date: 2016-03-24 23:30
Hasn't been mentioned:
The "screw" part of the rod is bend out of alignment with the "rod" part.
At first I thought the OP must be talking about the pivot screw at the bottom of the stack. However, I realize that "rod screw" must be the "screw rod". I see a lot of these coming loose. The screw rod itself can cause a key to bind.
I ran into this exact problem. I tightened the F# ring key screw rod (at the top of the topjoint "stack") and the F# ring key wouldn't move. The key fit between the posts, and moved freely on the rod...until I tightened it up. I discovered that the screw part of the rod (at the bottom) was bent out of alignment with the rest of the rod. You need an absolutely flat surface to roll the rod on to see this. When I tightened it all the way the screw part aligned with the threads in the post, which forced the rod part out of alignment . The key would move, but not freely, and stuck enough that the spring wouldn't move the key. I bent the screw back into alignment with the rod with a little plastic hammer, and the problem was solved.
- Matthew Simington
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Author: Chris P
Date: 2016-03-25 00:23
You'll often find the screw threads are very slightly eccentric to the rod screws on B&H and Peter Eaton clarinets - only that's down to the company that made the screws.
Another way to check the screw threads on rod screws are straight (or not) is to mount the threaded section in a bench chuck and spin it.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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