American PW Loose Roller Table

Dutto11

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Jul 12, 2006
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I have just replaced a staff in my 17jewel Riverside Waltham and when I placed the roller table back in place it was loose and just spins on the staff. The question I have did I put the wrong staff in or has the hole been enlarged, if so how do I tighten the roller table?
Thanks
Gary
 

bkerr

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Nov 29, 2007
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Do you have a beard? If so pluck a hair, put the hair between the staff and roller table. Trim once in place. I has worked for me and I learned from an old timmer.
 

Dutto11

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Jul 12, 2006
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This morning my time I tried an eyebrow hair with great success so thanks for the help.
Sorry I put this in the wrong forum it was late last night and I was at my wits end trying to fatham it out.
Gary
 

Don Dahlberg

NAWCC Member
Aug 31, 2000
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The proper solution to this problem is getting an appropriate staff. When you are about to replace a staff, place the roller on the staff BEFORE installing the staff. The roller should slip down about two thirds of the way. If is goes close to the bottom or to the bottom, then it will be loose. If it only goes down a bit, you may split the roller table when you stake the roller onto the staff.

Sometimes you cannot find a proper staff and you have to make it work. You do not want to modify the roller, because you would be breaking one of the most important rules of watchmaking. Never modify the watch to fit a part, modify the part to fit the watch. You would be creating a new problem to solve another problem.

The other way is to make the staff larger or fill the gap between them. This must be done in a way that keeps the roller table absolutely flat and concentric with the staff. The problem with the hair approach is that it destroys the concentricity of the roller table and staff. It fills the gap on one side, pushing the roller table away from the hair. If the gap is large and depending where you put the hair, this could cause the watch not to function properly or go out of action easily.

The shellac approach is better and is reversible. It is still hard to get the roller flat and concentric, but at least there is nothing pushing the roller to one side. If at some later date, someone goes to repair a broken roller jewel, they are surprised and angry when the roller falls of the staff on heating. That has happened to me.

Another similar approach is the use of oil stone powder in oil This is placed on the roller seat of the roller and the roller staked on. The grit between the balance roller seat and the roller fills the gap. Again, make sure the roller table sits flat and once you have the watch together, test it carefully in all pendant positions. Make sure the safety dart clears the roller by the same amount in all positions.

Don
 

Jake

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Oct 22, 2004
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Don, What's the big deal. The hair solution only offsets the roller table by a half a hair's breadth. Jake
 

Don Dahlberg

NAWCC Member
Aug 31, 2000
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Jake,

It depends on how loose the roller is. The big deal is the clearance between the roller jewel and the lever horns is small. A bigger problem is the proper clearance between the safety dart and roller is critical. If there is a place where the safety dart is too close to the roller, it will retard the action of the balance. If there is a place where the dart is too far, the watch may go out of action if it receives a jolt. Yes, I have seen the hair trick work many times. I have also worked on watches that keep going out of action, only to find the roller was not concentric with the balance.

How critical is it to have all parts of the balance concentric? Well, why do we have to cut the pivots of a balance staff on centers? Why do some watches stop running when the pivots get warn causing too much sideshake? Watchmaking is about hundreths or even thousands of a millimeter in some locations. The escapement is one of those places. By the way, a hair is about 5 to 10 hundreth of millimiter in diameter. Of course, it crushes when you us put it between the roller and staff. How far the the roller is off concentric depends on how bad the fit is originally.

Don
 

leghorn

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May 3, 2003
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I would like to know if anyone, who has used the" hair fix",has experienced any problems with the movement;as relates to the repair, after the applied solution. Just curious.



leghorn
 

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