I am servicing a Hamilton 16s 1908 model that has the hairspring out of flat and rubbing on the balance arms.

So I measured the height of the balance spring stud when all together and figured that I should just be able to tweak it until it was flat again and at the right height.

My problem is that when the balance is out the hairspring tends to flop back against the balance arms no matter which way is faces, almost like it's attracted to it. I've tried demagnetising to no avail.

The other option I guess is that it is slightly conical down towards the balance arms. Is it correctable, or should I just allow for it so that fixing the stud in position lifts it up a bit off the arms?

Regards

Peter (fiddling) in Oz

Hairspring adjusting is exacting work and without the correct hairspring tools can be very frustrating as well as damaging. If you don't have hairspring tools along with a good idea of what you are doing, best to leave it to someone who can show you the way.

Hey Roger, I have some tools, the inclination, and dealt with frustration...

However, I'm in country NSW with no one locally to guide me at present so moving on to more challenging stuff
like hair springs. Score so far is 1-1, not including this one.

Regards

Peter in Oz

Hello Peter...Have to admire your gutsy determination in the face of no mentor to help you. You might want to search for some reference books that cover hairspring adjustment if you haven't already done so.

Roger

Hi Roger, I have a few general repair books, de Carle, Fried etc, plus de Carle's book on hairspring adjusting but it doesn't have much on this.

Can the balance arms become magnetised? I know the spring can but not sure what the balance arms are made from. I think it is more likely this by the behavior as I can get the spring flat with a little tug in the right direction, and then after a few vibrations it flops again.

Will have to do a bit of gentle experimentations - fingers crossed...

Regards

Peter in Oz

Peter...The arms are steel and could become magnetized, but I doubt that is your problem. Easy enough to eliminate that possibility by putting both thru the demagnetizer. I'd do it with the hairspring in place. With the balance out and sitting upright, hairspring up, is the spring flat? Is the spring an overcoil? If the stud is leaning, when you put it in the balance cock the hairspring will tilt. Make sure the stud is perpendicular to the spring in all directions. If it still wants to cone down to the arm you will most likely want to gently pull up with hairspring tweezers on the inner coil on the low side. Once it looks good out of the watch you may have to tweak the hairspring using the outer coil and either good hairspring tweezers or a special tool with a slot in it made for forming hairsprings. You can usually push gently in different areas to get an idea what you would like to do before committing with a bend. You seem to have a great deal of patience, so you will probably 'win' in the end. Good Luck.

Roger

Well, after a bit of going and froing I managed to get the over coil flat again and the stud vertical. I think these were the two problems causing the arm rubbing.

Has taken me over a week, mainly setting it aside and thinking it through and then coming back to it. It's ticking away nicely now with a goodish arc - will have to see how it's going in the morning. Fingers crossed.

Certainly teaches patience...

Regards

Peter in Oz

Sounds good Peter. You definitely have the patience and the right approach to walk away and come back another time. Now that the balance is swinging without rubbing on the arms, check also that the overcoil is not brushing on the underside of the balance cock. The next thing I would do is remove the pallet (after letting down the mainspring of course) and put the balance back on the watch by itself. With a good flick of the wrist the balance should oscillate strongly and do so for a minimum of a minute and when it comes to an eventual stop it should smoothly stop with no jerky look to it. When it is stopped you can also do an initial check for beat by making sure the roller jewel lies pretty close to center between the banking pins by line of sight across the pallet jewel hole. Check the balance motion dial up and dial down and also vertically and at about a 45 degree angle to make sure the balance is oscillating well in all positions. I'm assuming you took apart the upper and lower cap jewels and cleaned and oiled them during your service and also examined the balance pivots for any problems.

Roger

A method if suspected over coil or stud issues is to separate hairspring from balance and mount it in the cock. Check the flat, curb pin radius, collet centered over balance jewel, over coil clearence and whatever else you can think of, now easier to see. Also nice holder to do some tweakin

Gents, thanks for all the tips.

This morning the movement is still going well, although the beat error is about 1.7ms. All this is face down so I'll have to check other positions later today. Balance jewels were cleaned and oiled prior to starting all this.

Paul, haven't removed the hairspring before, but looking back probably would have been easier.

Again, thanks for the suggestions and encouragement.

Regards

Peter in Oz