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Forum Contributor 2010, Distinguished SOTW Member
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Discussion Starter #1
A couple of days ago my Ref. 36 began to give me some trouble; notes from G down were stuffy (in both registers). It was subtle, but troublesome. I went back and forth wondering whether the problem was with the horn or with me. I used a leak light and found nothing. But the problem persisted. Tonight at a rehearsal, it occured to me to check for play in the keys, and I found some around G and A, which made me look REALLY closely, and at last I discovered a loose rod screw, on the bottom of one of the top stack rods, that was allowing a tad of play there. I borrowed a tiny screwdriver from the bass player (go figger), tightened it up, and Voila! Everything was copacetic again.

So the question is: why would a rod screw work itself loose that way? I had the horn gone over 2 months ago by a tech with an excellent rep. Should I wonder at all about his skills, or his attention to my axe? Or is this a "normal" occurance in the lifespan of a good horn? I've been playing for some 48 years, and never had this exact problem before.

Again, the screw in question is not obvious at all; it takes a close scrutiny even to find it.
 

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All bass players have tiny screwdrivers.:cool:

I think gunk gets built up around the screw, and eventually, through playing, it eventually loosens the screw. It doesn't really happen that often--it depends on the gunk.
 

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Discussion Starter #3
hakukani said:
All bass players have tiny screwdrivers.:cool:

I think gunk gets built up around the screw, and eventually, through playing, it eventually loosens the screw. It doesn't really happen that often--it depends on the gunk.
This horn is not yet 2 years old. I played for a long time a 1929 Chu Berry (still have it as a backup) that exhibited no such tendency. Though maybe young gunk is more flexible than old gunk. I notice that, now I'm nearly 60, a lot of my personal gunk is pretty rigid. . . .:D

Don't really know why gunk would build up on this one screw that points DOWN underneath a lot of other mechanism. . . .
 

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This is a problem we see most often with Yamaha 52 and 62 tenors and bari's. And the lower stack rod screw is equally a culprit, so keep an eye on that one also, if you didn't look at it already, even on your Yani.

In light of what Hakukani said, I suggest taking the entire rod out and cleaning all the key hinge tubes and rod, and oil with a SOTW recommended quality light/thin key oil. Then using a good screwdriver which has a tip to fit the screw slot on the rod properly, snug it in firmly.
 

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"So the question is: why would a rod screw work itself loose that way?"

It was not tightened properly in the first place. Only reason!
 

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The screw unscrews when the key that is on the screw turns because it is dragging. If the screw unscrews counter clockwise when the key turns in that direction it turns the screw. Play a lot of notes the screw comes all the way out.
 

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Discussion Starter #7
Gordon (NZ) said:
"So the question is: why would a rod screw work itself loose that way?"

It was not tightened properly in the first place. Only reason!
That is exactly what I thought.

So do I worry about a setup that happened 2 years ago, or a "tune-up" done by a different tech 2 months ago/
 

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I wouldn't worry about either. If it didn't start happening until recently, I would bet a new variable has been introduced. It could have been fine until a mote of dust landed in the right spot to create enough friction to start backing the rod out, or a slight knock you aren't yet even aware of bent your lower stack out of alignment, or the f# key bar is bent and causing friction, or a tolerance that was almost too tight to begin with started to catch once the oil starting breaking down, or...

Of course if you take this to be fixed and it keeps happening that is a different story.

FWIW, I have seen at least a few dozen people come in and the problem was just a screw backing out. The part that makes me earn my keep is figuring out why it was backing out and how to fix it so it doesn't happen again.
 

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I'm a bit confused by the terminology. There are pivot screws that hold the solid key rods in place at the ends and then there are pivot rods that are inserted into the hinge tubes of keys that the key rotates upon like a hinge.

If a pivot screw came loose, it could be a case of not being securely tightened or it could be a case of not being fit to the key well to begin with. Locktite on the threads when the key is reinstalled can help it to stay in place.

If a pivot rod comes unscrewed, it is always a result of excessive friction---either dry or gummy rods inside the hinge tube or by bent keys. It would be unfair to blame the last person who worked on the sax without first discovering the underlying cause IMHO.

John
 

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jbtsax said:
...
If a pivot rod comes unscrewed, it is always a result of excessive friction---either dry or gummy rods inside the hinge tube or by bent keys. It would be unfair to blame the last person who worked on the sax without first discovering the underlying cause IMHO.

John
So how come I have come across so many loose rods on almost new instruments, with no evidence of damage, no pivot binding etc.

If a stack key gets bent so much that its movement takes the tightly secured pivot rod with it, the the tube will be sufficiently jammed on the rod that the rod will not unscrew any further unaided.

And it is inconceivable that dust etc could release a tightly done up pivot rod.

BTW I know local technicians who purposely leave rods loose. I guess that is to encourage the instrument into a state that it needs to return for servicing sooner.

The only other reason is that there is a problem that would cause the tube to bind if the rod was screwed in tight. If so, then the problem - say a burr inside the end of the tube, or the threaded part bent, or the thread in the post out of line with the other post - should be dealt with - and then the rod screwed up tight.

In my book, ZERO excuses for rods working out after servicing.
 

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I'm going to side with JBT on this one. If there wasn't some sort of friction, how would it work itself loose even if it was partially unscrewed? Partially unscrewed, it still would take some sort of force to unscrew it- or screw it back in. Why would a rod with no problems work itself out in one direction (counterclockwise), when the keys travel equal distances in two opposite directions? Remember your laws of physics here.

And how is it inconceivable that dust etc wouldn't introduce friction if it got into a hinge tube? I think that is just common sense- tight fit between the hinge tube and the rod, introduce something as larger or larger than the tolerance between the two surfaces, voila- friction. If grit and dirt didn't cause friction, we would never change the oil in our cars.

Purposely leaving rods loose to try and generate business sounds ridiculous to me. If there is no underlying problem, you just screw it back in! I don't know about you, but I wouldn't feel right charging someone for 5 seconds worth of labor.

Saying there are ZERO excuses for a rod working itself 2 months after a servicing is unreasonable, IMHO. If it were the repairmans fault it would have worked itself out in the first 30 minutes of playing after he got it back.
 

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I think it's sloppy/loose fitting threads if everything is straight, cleaned and oiled properly. As I mentioned above, we see it frequently on Yamaha's, even ones less than a year old and no damage to anything. Note that the rod screws always work their way out and UP, so gravity has nothing to do with it. It's the first thing we check whenever we get these instruments in the shop, as it's so common.

On a similar note, consider this;

Why do hinge pins on doors (which are inserted from the top) always work their way out/up? You would think that gravity alone would keep this from happening. :?
 

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Discussion Starter #14
Thanks! All this sounds reasonable to me. Of course one can never be sure why something like this happens. And I wasn't implying that the tech had left a screw to come loose on purpose, but that perhaps in the process of disassembling and reassembling hadn't snugged it down properly. I can't see that anything is bent, and the horn has suffered no known blows, except me blowing it. And all is well for now, but I'll be alert for any further troubles that might be related to this; your information is extremely useful there.
 

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Discussion Starter #15
griff136 said:
:) am i right in saying you turned a bass into a viola just using a small screwdriver? -wow ! he he he
Yes, I'm an unusually gifted guy! Lol.
 

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abadcliche said:
I'm going to side with JBT on this one.
And I'm going to agree with Gordon :) :D

abadcliche said:
If there wasn't some sort of friction, how would it work itself loose even if it was partially unscrewed? Partially unscrewed, it still would take some sort of force to unscrew it- or screw it back in. Why would a rod with no problems work itself out in one direction (counterclockwise), when the keys travel equal distances in two opposite directions? Remember your laws of physics here.
But there is always "some sort of friction". There always is (even with oil) between a key and rod. If there wasn't the rod couldn't support the key! So the question is why with the normal/good amount of friction the rod will screw itself out and not in.
First of all, how would you know if a rod is screwing itself in? I'm guessing... you wouldn't! So the question is how would the screw move more to one direction than the other with normal/good friction. Maybe because one direction has more friction than the other, possibly because of the speed of the key, the position of the key on the rod (there is always a tiny gap between the rod and key, no matter how tiny it is) can possibly be different whether the key is open or closed, etc. Maybe it is harder to screw the more it is in so that's enough to not let it screw more in. Lots of possibilities.

abadcliche said:
And how is it inconceivable that dust etc wouldn't introduce friction if it got into a hinge tube?
No one said dust wouldn't introduce friction, only that dust wouldn't cause a rod to screw itself loose (in a case where otherwise it wouldn't).

abadcliche said:
Saying there are ZERO excuses for a rod working itself 2 months after a servicing is unreasonable, IMHO. If it were the repairmans fault it would have worked itself out in the first 30 minutes of playing after he got it back.
Maybe I am more forgiving than Gordon :) I wouldn't jump at the repairer either. But it can take a lot of time for the screw to work itself out and won't necessarily happen in the first 30 mintues of playing. The way to know how long it took is when you see it is loose, try to remember when it wasn't :D
 

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There are many forms of vibration which tend to move something in one direction more than another. This principle is used to transport items in a certain direction. It is also one reason why left hand threads are sometimes used.

So both the acoustic vibrations in a sax, and the movement of the keys up and down, can indeed tend to progressively undo a screw. On releasing a key, the various forces on that key are slightly different than for closing it.

However I re-assert that this loosening process would never have started, if the screw (or rod) was tightened securely in the first places. the various forces would not be sufficient to overcome those that hold the screw secure.

I don't think the most recent technician should necessarily be blamed for a loose screw.

If I checked every screw for tightness, every time an instrument came in, that would be just one of the many things I can do that eventually bring the bill to more than many players want to pay.

Certainly, for regular customers, I tend to assume the screws are tight.

However if I find a few that are loose, I check the lot, or if the instrument has the sticker of a certain local "technician", I know I have to check the lot.

If I do a pre-sale service of a reasonable instrument, then I check all screws, and there are often some loose ones.

However, on a very low quality, brand new instrument, there are often screws and rods that if tightened, jam the mechanism. To correct the underlying faults could easily cost a significant portion of the purchase price, which such customers are not happy with! To some degree, such customers have to live with their mistakes!
 

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clarnibass said:
And I'm going to agree with Gordon :) :D
But there is always some sort of friction
Especially on SOTW. :)
clarnibass said:
First of all, how would you know if a rod is screwing itself in?
I have a good answer to this, but I don't want to get Martysaxed. ;)
clarnibass said:
Maybe it is harder to screw the more it is in so that's enough to not let it screw more in.
You can say that again. :) By the way have you ever heard of Yogi Berra?

All I can say is I have never heard of a screw or rod "working its way tight" on a saxophone. :D
 

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"This is a problem we see most often with Yamaha 52 and 62 tenors and bari's. "
I agree with Jerry here. Add YAS23 altos to the list. The first place I look on these is the upper and lower stack rods. Clean 'em, oil 'em and make sure everything is aligned as well as possible. (They still work their way loose eventually.) I tell all the students to watch these spots.
Hans
 
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