I have a 18s Hampden and when I was putting it back together the screwdriver slipped when tightening the screw that holds the hairspring stud in the balance cock. It hit the stud and broke the hairspring off flush with the stud end. Any suggestions on how I can fix this? Thanks in advance for any suggestions.

Hey Jim, I think you will need a new hairspring. The stud can be reattached,but the hairspring will then probably be too short for the watch to keep good time. I recently did pretty much the same thing with an Elgin keywind,and after reattaching the hairspring,I had to add more screws to the balance wheel to slow the watch down to the right speed. A hairspring for that watch shouldn't be hard to find. As for how to reattach the hairspring,if you look close at the stud,you will see it is pinned with a tiny brass pin. Push out the pin,reinsert the end of the hairspring into the stud,and put the pin back in. Sounds easy,but unless you have some patience,and very steady hands,it's pretty hard to do. Well, for me anyway.

I forgot to add,after the stud is reattached,the stud will be in a different position in regards to the roller jewel,and the hairspring will have to be readjusted to get the watch back in proper beat.

Thanks Cecil, Im at least going to try that before looking for a replacement. I probably will have to move the spring a little by the grove in the collet if I can get it back on the stud. There is plenty of open places for timing screws if I need to add them. The watch is a Meno Park I picked up for $60 and I was only planing on displaying it, but I like the ones I display to at least be able to tick.

Follow up:
After playing with it for about an a hour and a half I gave up, took a look through my parts movements and found a hairspring on a duber with a broken balance shaft.

If you have some MicroTaper Pins to lock the spring back into the stud and IF the amount of hairspring "lost" is only that which was in the stud, you can probably successfully re-attach the stud to the broken end.

Be very careful to hold the stud in the same orientation as it was (for inserting into the Balance cock) originally. To do this I use a small Balance weight tweezer chuck.

When it is successfully re-attached, to compensate for the watch timing, I use balance screw timing washers to "bulk up" the wheel mass and approach correct "vibration" (timing) with the newly shortened Hairspring.
I have done this successfully about a dozen times, just be careful.

Thanks David
I gave up last night because it was so late and I couldnt get the taper pin out. But I kept the spring and the stud, perhaps they will come in handy in the future. Perhaps it will be easier as my tool collection grows, or I progress in working on small things.

Dave,
Two questions regarding this old post.
Where do you get MicroTaper Pins....
And, what is a small Balance weight tweezer chuck?

I need some brass pins for hairsprings, dials, etc.

And, I need a better way to hold balance wheels and hairsprings when assembling.

hi dave,
if you can find some old guitar strings one of the 3 bottom strings is just right for dial pins. make sure the strings are brass and medium gauge. you can grind a point on one end or use it as is.
leonard

Thanks Leonard, I can probably find some of those.
What I really need right now is a hairspring pin. Maybe I can figure out how to grind it or file it to a taper?

Dave Turner,Give me your address and I'll send you a few pins.Regards,Norm

Thanks Norman,

It's the little things like this that make it difficult for someone new.

Thanks so much,
email sent.

Dave

Dave,
Norman is going to send you a few tiny slivers of brass. Thats how best to describe hairspring pins. Its a pin that is used to wedge the hairspring into a hole on some hairspring studs.
I gave up on the hairspring in this topic. I eventually was able to pickup another donor movement that eventually fixed the topic one and 2 others. Anytime I can fix 3 movements from one parts movement I count myself lucky.

Jim,
You were lucky. Seems like every time I buy a parts movement it doesn't have what I need as a donor and then I have one more watch laying around that doesn't work.
It's kind of like eating bread and honey. You never run out of both at the same time.
Evidently the solution is to accumulate a whole pile of used parts.

LOL
Ya, it happens more often like you say. But over time I have gotten quite a few parts corpses. I like to buy multiple movements in a lot. Last one I got was 6 18s Walthams on eBay for about $60. Two of them worked great. So I figure the others are a bonus.
I have also resold a movement that didnt have the parts and recouped my cash. One of the nice things about getting 50 free listings a month on eBay.
But the one that started this topic was a average open face hampden. I used the hairspring on one, the pallet fork on another and the winding gears on a third. I still have the rest in a container. Perhaps I can use them some time. Perhaps for a jewel. To bad it has a broken seconds pinion or Id have a 4th.

Sounds good. Maybe when my 'junkyard' gets big enough, I'll be able to starting matching up pieces.

Norman,
Got the brass pins today. Thanks! That's what I call service. Those should do me for a long time to come.