Need help with hands

[Broam]

I just replaced the chronograph hands on an old watch that has a Valjoux 7734 movement in it. The new hands appear to sit a little higher due to the stems being slightly longer. Now the hour hand hits those chronograph hands. I think there is room to make adjustment. It would require bending the minute hand then the hour hand slightly. What is the procedure for doing this? Can it be done with the hands still on the watch? Thanks!!!

[noirrac1j]

You can bend the tips of the hour hand slightly to clear the chrono hand, or you can also take a fine-cut file and reduce the height of the stem a little so that is doesn't interfer. You can bend the hands while still on the watch with brass tweezers. Be careful not to slip and scratch the dial.

 

J

[Ishima]

Id be tempted to remove the sub dial hands, grip them by the arbor ('stem') and rub the arbor on something like an Arkansas stone until they're the desired length. Tweaking the tilt of the hands is also doable, but less ideal, it might make them look slightly 'wrong' if nothing else. That being said I have done it a few times, my preference is for using some pegwood with a wedge-shaped tip and to push up on the hand from underneath, no metal to mark the hands and dial and you're also not touching the top of the hand. (unless you go to far and have to push it back down)

Perhaps obviously: just make sure the hands are at different position so they're not getting in the way of the hand you're trying to bend and go little by little. 

Edited November 27, 2017 by Ishima

[szbalogh]

Reducing the pivot length wont make any difference in the hand height, since the pivot is conical. Best way is to make the hole on the hand a bit bigger with a broach. 

Bending the hand on the pivot is a bad idea. Lifting the tip of the hand exert a great torque at the pivot making it to bend... worst, it can stick in the hole or break. 

The rule always applies that dont make any change on the original parts which were doing fine before the service. Make change to he parts which are new!

[oli]

Yes I agree I would broach the new hands to open up the hole so that they sit a little bit lower. The broach will give the hand pipe a nice taper. Take it slowly as you can't put material back on once it's gone! 

[rodabod]

I agree with broaching the collet. For smaller collets, I use a needle.

Also make sure that the hour and minute hand collets are not just worn/too wide. I usually tighten them when necessary with a jewelling set.

General rule is to aim for a gap of one-hand's-thickness between hands. It's a bit vague, but it's a starting point.

Edited November 27, 2017 by rodabod

[Ishima]

Broaching may be the better procedure, but if you have a hand arbor of generous length and it's sitting too high i maintain you can achieve the same result by shortening that arbor, because quite simply, the hand is lower before you even start to press it on, so of course the friction will max out at a point with the hand being lower than before. The fact that the pivot is a conical point doesn't negate that, not in my experience.

Edited November 27, 2017 by Ishima

[noirrac1j]

10 hours ago, szbalogh said:

Reducing the pivot length wont make any difference in the hand height, since the pivot is conical. Best way is to make the hole on the hand a bit bigger with a broach. 

Bending the hand on the pivot is a bad idea. Lifting the tip of the hand exert a great torque at the pivot making it to bend... worst, it can stick in the hole or break. 

The rule always applies that dont make any change on the original parts which were doing fine before the service. Make change to he parts which are new!

You guys are overcomplicating this. Ive reduced the stem height on hands with a fine cross-hatched file and it DID reduce the overall sitting height. ThEre is no need to broach, and all that can happen is the hand may no longer sit snugly on the pivot. I've also slightly bent the tips of sweep second hands to that they  clear crystal/glass  and also slightly bend them upward IF they happen to hit  each other.... I'm taking small amounts of torque not using a ham-fisted approach...sheesh!

J

Edited November 27, 2017 by noirrac1j