Beat error change after bezel repalcement

Paul Raposo

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Nov 4, 2005
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I was replaced a bezel on a watch for a fellow collector. It's a Seiko diver SKX007 and originally came with a black bezel and he asked me to install a red/blue bezel.

Before starting the work I put the watch on my timing machine and it was running +6 with an amplitude of 270-285 depending on positions with a beat error of 0.2.

After installing the bezel by putting the watch dial side down and pressing down on the case back to snap the bezel into place I checked the timing again. Everything was as before except now the beat error is 0.6.

Did I mess something up by pressing down on the case back and snapping the case down onto the bezel? The beat error is ok, but why the change after doing this work?
 

Skutt50

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I agree with Karl, did you check in the same positions?

You could have accidently touched the regulator holding the hairspring (which is how you adjust beat error) but if doing so the other parameters would change as well.....
If you did not touch it the only other possibility I can think of is that the reglator was moved by the shock of the movement when you snapped on the bezel. I do however think this is very unlikely..........
 
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Paul Raposo

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That's strange. Is the beat error the same across positions? Are you certain you checked the beat in the same positions before and after?
The beat error goes from 0.6ms to 0.7ms depending on the positions. The rate and amplitude varies slightly, but not much different from before.

Before the bezel change I checked the rate, amplitude and beat error in all positions. The rate and amplitude changed a bit in different postions but the beat error remained at 0.2ms in all positions.

If you did not touch it the only other possibility I can think of is that the reglator was moved by the shock of the movement when you snapped on the bezel. I do however think this is very unlikely..........
That's what I wondered, if the shock caused the stud carrier to move, or caused the spring to touch somewhere against itself, but he change is so small that I'm not sure. The case backs on these are screwed down pretty tight--and it's not my watch--so I didn't want to try and remove the back to check the hairspring.
 

karlmansson

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The beat error goes from 0.6ms to 0.7ms depending on the positions. The rate and amplitude varies slightly, but not much different from before.

Before the bezel change I checked the rate, amplitude and beat error in all positions. The rate and amplitude changed a bit in different postions but the beat error remained at 0.2ms in all positions.



That's what I wondered, if the shock caused the stud carrier to move, or caused the spring to touch somewhere against itself, but he change is so small that I'm not sure. The case backs on these are screwed down pretty tight--and it's not my watch--so I didn't want to try and remove the back to check the hairspring.
In some movements where the hairspring isn't captive with a dogleg type regulator (or those bizarre extended leg versions) a sharp jolt at the wrong time can make the spring pop out of the gap in the regulator. That would probably show up as a greater error than a 0,4ms beat error increase.
 
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Paul Raposo

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In some movements where the hairspring isn't captive with a dogleg type regulator (or those bizarre extended leg versions) a sharp jolt at the wrong time can make the spring pop out of the gap in the regulator. That would probably show up as a greater error than a 0,4ms beat error increase.
Good point, Karl. From what I remember the Seiko springs are held inside a closed regulator with a surprisingly wide gap.

 

Whereisitat

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Mar 14, 2017
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Well-In the picture the hairspring has uneven coils. It may be the way it is sitting canted or not centered.

But if it is deformed or more likely-not centered in the regulator pins it may be the reason. It is hard to see on the Seiko's but try to verify the hairspring breathes between the regulator pin. They are adjustable for gap with a special tool to turn the pins. The point is if the gap is too small, or the hairspring is not centered & "breathing" it is likely to hang up slightly out of kilter even after a minor jolt making the beat unreliable in readings.

Hairsprings are often jostled without knowing and it doesn't take much.

Disregard if it checks out. Flat & true with a even breath is always a must.
 
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karlmansson

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Well-In the picture the hairspring has uneven coils. It may be the way it is sitting canted or not centered.

But if it is deformed or more likely-not centered in the regulator pins it may be the reason. It is hard to see on the Seiko's but try to verify the hairspring breathes between the regulator pin. They are adjustable for gap with a special tool to turn the pins. The point is if the gap is too small, or the hairspring is not centered & "breathing" it is likely to hang up slightly out of kilter even after a minor jolt making the beat unreliable in readings.

Hairsprings are often jostled without knowing and it doesn't take much.

Disregard if it checks out. Flat & true with a even breath is always a must.
Since Paul didn't have this watch apart I suspect this is the balance cock of a different watch of the same caliber.
 
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Al J

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The only thing that comes to mind would be that the jarring from the seating of the watch onto the bezel, may have caused the balance to move the jewels in the shock protection, and they have not settled back to the exact same location as they were previously.
 

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