For a watch to “bank” because of a problem with a gripping bridle, the amplitude of the balance wheel would have to be closer to 650° Or more for the roller jewel to strike the pallet horns on the outer surface. The one quote in the link indicated it would bank at about 360°. Not possible.
This sounds like it might be the same problem. Although if so, the watchmaker must have made a similar mistake when servicing both movements:
https://www.thewatchforum.co.uk/ind...-m177s-gain-time-while-i-was-walking-the-dog/
I'm waiting for both watches to wind down, and then I'll take each of them for walkies...
How much should I wind them to get them going first? I guess you wouldn't want no wind at all in the mainspring, as that in itself could cause inaccuracy?
How about if I give five winds of the crown to get the watch going and then immediately go for a walk? Or just one or two winds, or ten?
For a watch to “bank” because of a problem with a gripping bridle, the amplitude of the balance wheel would have to be closer to 650° Or more for the roller jewel to strike the pallet horns on the outer surface. The one quote in the link indicated it would bank at about 360°. Not possible.
So... I took one of the watches for a walk yesterday morning after letting it run down (I gave it 4 winds to start it up). It kept perfect time.
However.. after wearing the watch for the rest of yesterday and for a few hours today I went out again, expecting to see it gaining time again in the fully-wound state while walking. But after 40 mins of walking it was still spot-on. I then gave it 40 winds of the crown just to make sure it was fully wound and kept walking for another 20 mins or so, but it stubbornly remained accurate to the second!
So now I am just mystified.
Is there a difference between "rebanking" and "overbanking"?
Yes, overtaking is when the impulse pin ends up stuck on the back side of the pallet fork horn.
Rebanking, or knocking, is when the impulse pin touches the back of the horn and then comes back around. Basically, the balance has travelled too far.
Thanks. I have a 2" Ansonia clock movement that some "repair person" (dipstick) put way too strong of a mainspring in so I want to use the right term when I bring it to the clockmaker.
It's still very possible that it's rebanking. To determine definitively you would need to check the amplitude on a timing machine, as has been mentioned previously. It's possible that it won't rebank on every occasion. Any watchmaker will be able to check it on a timing machine for you.
Just wondering: is there a typical amplitude range that alerts one to the possibility of re-banking?
It does depend on the movement. Come caliber’s have lower amplitude upper limits than others. If you are seeing 320-330 degrees at full wind you have a very high chance of rebanking, if it’s an automatic watch. It also depends on the efficiency of the automatic winding system being used. There was talk in a previous post about rebanking being impossible at 360 degrees. Really don’t know what that is about. If a watch balance has amplitude of 360 degrees it’s rebanking.
Omega state that amplitude shouldn’t be above 315 for an automatic watch in the dial up position and 325 for a manual wind watch.
Again, movement specific. A rolex 1530/1570 has an upper amplitude limit of 280 degrees.
Personally, I think 280-300 in the dial up is around the right spot.
What I find curious is that high amplitudes occur in the horizontal positions (dial-up, dial down). These are not the positions that occur when walking. Significant re-banking in vertical positions appears unlikely to me.
