How to make an overcoil

[Nucejoe]

Found this vid on the Net, shows how to make a breguet  overcoil.

 

 

[mikepilk]

Very impressive. I don't imagine it could be done without the special tweezers. 

The times I've had to tweak overcoils has given me real problems - resting the tips of the tweezers on the surface risks damaging the "flat" coils. That's how I trashed one hairspring, by realising the tweezers while the tips were still in the coils.
Maybe it's possible to slide a thin bit of plastic under the overcoil when working on it ? 

 

[nickelsilver]

It can be done without the special tweezers. I don't make overcoils very often, more likely I might modify the overcoil curve to correct isochronal error, and it's quite rare for me to dig out the special ones in either case. They are nice to have though.

[mikepilk]

2 minutes ago, nickelsilver said:

It can be done without the special tweezers. I don't make overcoils very often, more likely I might modify the overcoil curve to correct isochronal error, and it's quite rare for me to dig out the special ones in either case. They are nice to have though.

When modifying the coils, what is your technique, do you have the tweezers hovering in the air above the lower coils?

[nickelsilver]

18 minutes ago, mikepilk said:

When modifying the coils, what is your technique, do you have the tweezers hovering in the air above the lower coils?

Yeah, pretty much. I'll grip the overcoil somewhere with one pair, then tweak with another where I want to modify the curve. This is with the spring off the balance. In the watch, if space permits, you can often do a lot with just one pair of tweezers- in fact one of my hairspring teachers pressed on us that it's always better to use one pair if at all possible; when you get two going you can mess things up very quickly. Out of the watch you need a second pair though.

[ifibrin]

1 hour ago, nickelsilver said:

Yeah, pretty much. I'll grip the overcoil somewhere with one pair, then tweak with another where I want to modify the curve. This is with the spring off the balance. In the watch, if space permits, you can often do a lot with just one pair of tweezers- in fact one of my hairspring teachers pressed on us that it's always better to use one pair if at all possible; when you get two going you can mess things up very quickly. Out of the watch you need a second pair though.

How many hairsprings did you have to go through while learning this? Working on hairsprings while the hairspring, balance wheel, and balance cock still in the movement sounds very difficult! Sounds like everything else will be blocking your view!

[mikepilk]

4 minutes ago, ifibrin said:

How many hairsprings did you have to go through while learning this? Working on hairsprings while the hairspring, balance wheel, and balance cock still in the movement sounds very difficult! Sounds like everything else will be blocking your view!

I often tweak the terminal curve whilst the balance is in the movement. I can sometimes adjust the flatness of the spring using a fine oiler to get under the coils - depending on the access. 

As @nickelsilvernotes, your are less likely to do damage with one pair of tweezers.

[nickelsilver]

10 minutes ago, ifibrin said:

How many hairsprings did you have to go through while learning this? Working on hairsprings while the hairspring, balance wheel, and balance cock still in the movement sounds very difficult! Sounds like everything else will be blocking your view!

We learned in school, starting with huge alarm clock hairsprings, working down to small ladies size springs. So actually didn't destroy very many. The teacher would put in bends in the round, we'd correct, then bends in the flat, correct, then both and several of them. For some students it was hellish work, but in the end everyone became very competent.

 

I would say 90+ percent of hairspring work gets done with the spring in the watch. I adjust probably 2 out of 3 springs that pass through my hands, pretty much always in the watch. Exceptions would be if I need to true it at the collet, or if a spring is severely out of true (mangled). Truing at the collet is done with the balance held in calipers (there are specific ones for truing springs), and mangled springs will come off the balance and brought back to shape, then trued in the watch.

[mikepilk]

1 hour ago, nickelsilver said:

We learned in school, starting with huge alarm clock hairsprings, working down to small ladies size springs. So actually didn't destroy very many.

I did destroy the hairspring on a ladies Omega 455 movement I have. At about 3.5 mm diameter, even my finest tweezers seemed massive. The more I tweaked, the worst it got.  One day I hope to find a (cheapish) replacement balance, but I've been searching over a year.

I think a spring that size would get even your full attention !

Just dug it out for another go, and managed to get the tangle out - it's looking a lot better. Maybe I will have a chance. Problem is the metal is VERY soft. A couple of bends in one place will snap it.

Edited June 30, 2022 by mikepilk

[Nucejoe]

Hi Mike

 I too  find soft spring difficult to work on. I can imagine a overcoil to be more challanging to shape on soft springs. 

Not a bad record if you have only destroyed one overcoil , hate to have to show you my bin. 

 

 

[mikepilk]

57 minutes ago, Nucejoe said:

Hi Mike

 I too  find soft spring difficult to work on. I can imagine a overcoil to be more challanging to shape on soft springs. 

Not a bad record if you have only destroyed one overcoil , hate to have to show you my bin. 

Fortunately this isn't an overcoil, but as you can see from the scale in the pic, it's tiny !

[Nucejoe]

Special tweezers No 9, is adjustable for spring's thickness and bent up .

Shown here.

 

[jdm]

43 minutes ago, Nucejoe said:

Special tweezers No 9, is adjustable for spring's thickness and bent up .

We had various discussions about hairspring tweezers in the past. It's always worth to mention for the casual reader that these are not made anymore, one can possibly find some NOS pieces but beside the extorsionate price, only the tiny sizes are offered, not meant for men watches.

[LittleWatchShop]

This is a great video.  I found it awhile back and watched it but it was good to see it again.

I have to do this on my Cyma hairspring but I do not have the bending tweezers (either one) so I guess I will use the technique I saw on another video where the hairspring is held tightly with a tweezer and pressed into a block of wood.  A little scary...but...

[mikepilk]

17 minutes ago, LittleWatchShop said:

I have to do this on my Cyma hairspring but I do not have the bending tweezers (either one) so I guess I will use the technique I saw on another video where the hairspring is held tightly with a tweezer and pressed into a block of wood.  A little scary...but...

I used the technique with a block of wood to flatten a bent spring - it works really well. 

[LittleWatchShop]

I just ordered a pair of Dumont #10, because I can.