hi everyone, todd here
i have been struggling with this for the past 4 hours before turning to you and have searched the site but found no answer.
i have been working on an old elgin sz.3
did the full cleaning on it and am quite proud that this is the first time i haven't had to consult my step by step disassembly pics to figure out what goes where. i am getting to the point where i know what goes where. feels good.

so, this is my problem, i installed the balance before the fourth and escapement wheel, and pallet so i could look in and check that i was in beat. what i found was that i was in beat but if i gave the balance a slight spin left or right it doesn't come back to being in beat. first thing i thought was bad or broken pinion. so i pulled out the balance and the pinions look ok to me.

other side looks ok too

so next i think hairspring problem, looked at that and it looks ok too.
but i wanted to isolate the problem so i removed the hairspring from the balance and put it back in the movement without the hairspring.
it moves freely and smooth as silk, very little shake in any direction. much better than with the spring in place.
so i reinstalled the spring and back into the movement without the stud in the balance cock. smooth as silk again.
as soon as i put the stud into the balance cock, sluggish again.
is it possible the hairspring stud is twisting the spring in some way causing it to rub somewhere i can't see?
could this be causing the sluggishness in the balance or is there another possible cause?
and what are my possible solutions?
sorry this post is so long but i wanted to properly describe my process so far.
i have had this balance in and out of the watch so many times i have lost count.
thanks everyone
todd
P.S.
hi David, these last 4 hours have really taught me a lesson in the patience you mentioned the other day!

Just a guess, possibly magnetized?

put the hairspring in the cock and look and see if the collet lines up with the jewel in the balance cock if not you will have to correct the overcoil.

i think i found the problem,
the overcoil seems to be bent too much towards the cock.
it arcs up then back down to the stud. other hairsprings i have don't look like this.
i think it is rubbing on the bottom of the cock where i cant see it.
how hard is it to reshape a hairspring?
about to learn something new!
wish me luck!
todd

I hate hair springs. Just take you time, work on a surface where you will not drop the cock and still have the hair spring in your hand.
Take progress pictures so you can go back if you need too. Their are tools that I have that are for bending the coils a little at a time. Specially bent tweezers and so forth.
I got these from a Salt Lake City time lock, watchmaker Who died two weeks before his 100th birthday. so I have no Idea where to get them.

2.

4.

hi Patrick.
i love time locks!
i had a double set from an old chubb mosler vault here in Montreal.
traded it for a really nice Gruen curvex.
but it was so pretty and well made.
i wish i still had it.
todd

Todd,

Welcome to the world of hair springs. Sometimes, there is a slight bend right where the hair spring enters the stud. The stud should be dead vertical when the spring is sitting on the table. If it is bent off vertical, when you secure it to the balance cock, it will flex the over coil up or down and cause it to drag on the other coils or on the bottom of the balance cock.

When the stud is secured to the balance cock, most assemblies finish with the stud perfectly flush to the top of the balance cock. If the stud is set too deep (remember you are coming bottom up... so it will be exposed on top) This will move the over coil up and make contact with the bottom of the balance cock... try pushing the stud back down toward the hairsping a fraction of a millimeter deeper in the socket and see what you get.

This is much easier to correct and much more likely to be the culprit than a misbent over coil.

I take a measurement from the center of the upper jewel in the balance cock to the center of the mounting hole for the stud... then I measure from the center of the hairspring to the stud.. these two measurements need to be a dead match... if the measurement on the hair spring is larger, it will flex the coils to the left... if the measurement is smaller... it will flex the coils to the right... It changes the geometry of the entire coil causing them to either sister up or to drag.

hi Paul,
i have been playing with this problem for a few days now.
i am sure of two things.
the overcoil is definitely out of shape and the stud is not square to the cock.
i have not yet attempted to fix this.
i am reading my frieds manual and looking all over the net.
before i try to fix it i want to be sure i am going about it right.
i love a good problem.
it is how i have always learned.
find the flaw, figure it out, fix it.
todd

In Freid's book, I gives a general radius and relation to the coils below it... Like, the over coil is almost above the second coil in the main section... For me, that translated in to a general relationship.

I focus on getting the center to center on the hairspring collet to the stud to match the balance cock... and the center to center from the collet to the portion of the hair spring that rides in the regulator guide pins to match the center to center measurements on the balance cock.

If the overcoil radius is not consistant in the guide pin range and matched to the arc the pins travel when we adjust the needle... it will bias the hairspring toward the center or away from the center when we push on the regulator needle.

I discovered this on a watch that would respond to the regulator in a certain arc... say, slow to center... but as soon as I crossed center... the watch would jump 100 beats per hour... a clear indication of sistered coils. Once I corrected the arc in the over coil in the range of regulator guide pins... it quit pushing the hair spring off center rotation and the coils quit sistering up.

hi Paul,
the more i look at this hairspring the more i am convinced that the stud is the problem.
it is not sitting at 90 degrees when at rest.
i think when i put the stud into the cock it is twisting the hairspring up against the cock.
unfortunately i cannot do anything about it right now.
my left arm is in a cast from finger to shoulder for the next 2 weeks.
i sit here at my computer typing with 1 hand looking longingly at my work bench.
todd

Some things are more important than conquering a watch.

Get healthy my friend!

Just imaging how much time that frees up for research and shopping though.