Can I ask the experienced watchmakers and tinkerers here...do you check the poise of the balance and true every train wheel before assembly? If so, how, as this is something I'd like to learn if possible.
I'm wanting to learn how to check the poise of the balance and also how true that escape wheel is or third wheel etc.c and I see the calipers on eBay that I'd like to test out.
What's the process with these tools if a wheel shows it's out of true?
I assume the pivots are gripped carefully by narrowing the tool with the roller in the middle, and the guide is used to observe the rotation. Does the guide get used to shape the wheel to true it by applying pressure against the area where there is clearly some warping?
Lastly, poising. With a balance, say on a Seiko 7002 for instance where a replacement would possibly be easier, although that in turn would or could mean the hairspring would need some slight shaping, would you check poise of say a few spares and determine which is best and use that with the hairspring that was removed, or indeed shape the balance as above and then check poise to determine if any material should be removed?
Is this common practice or is this overlooked? I assume that these two issues, cleanliness and correct lubrication aside, would affect positional variation the most thereafter?
Also what's the method to remove any weight from an out of poise balance? I am not sure if I'm confusing things here but wouldn't a wheel that needs truing be likely down to the pivot being bent and if so I assume the next step is to shape the pivot or replace the staff?
Although I suppose that is a whole different subject and ultimately straight pivots can still mean an out of true wheel, as a result of damage or mishandling etc?
I’ve no idea what your skill level or current capability is, but using these calipers is quite advanced. I have one but it rarely sees the light of day, mine was bought second-hand.
Best way to check train wheels is in the movement, far easier than fannying around with the caliper.
Unless a new balance staff has been fitted it’s generally not necessary to start trying to correct poise errors in the balance.
Paul
Guy, if you buy Donald de Carle's Practical Watch Repairing (old but very good) there's a section on poising that explains how to use a set of calipers. As Paul said there's usually no need to poise a balance unless it's been re-staffed and even then I prefer to use a poising tool as opposed to calipers anyway. You can see if train wheels are out true by spinning them in the movement, you'd use a caliper to check for trueness after correcting one.
Thank you both. I sometimes see a slightest wobble in say an escape or fourth wheel that I simply replace at the moment. I will spend more time on hairspring centering, how it runs through the regulator and ultimately keep aiming at high levels of cleanliness and correct lubrication to get the most out or the movements I'm working on. Replacing parts being the more effective solution. It's an interesting subject. Had some great responses aswell from Noah on scwf where I was really trying to work out how feasible it would be to turn a 7s26 into a superlative chronometer! :)
Cheers again, it will be something I have to start to develop skills at repairing on movements where replacements aren't as common at some point, also looking at depth to lock end how that affects amplitude is an interesting subject that was touched upon on scwf.
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