Bent hairspring out of beat

[Cymorill]

I'm hoping for a little help with an Elgin #17,000,000-ish 16s 7j hunting case 3/4 plate movement that is not running. I don't have the serial number in front of me at this moment.

After an ego-bolstering success with my first two watch repair projects (cleaning, replacing a mainspring, nothing grand), my mother approached me about seeing if I could repair a pocket watch that was left to her. It was my great-great-grandfather's watch (the serial number doesn't seem like it would be that far back in my family line, I know, but I'm only 32 years old). Besides being horribly dirty, the hairsping was somewhat mangled. It looked as though the spring had stuck in the regulator pins (probably due to dirt) and someone had rotated the balance wheel a few times causing the outer two coils of the hairspring to be bent outward and twisted back on themselves. I've spent about five hours' worth very gently bending the hairspring back into shape with pliers sharp enough to poke holes in my fingers, and it now resembles a nicely coiled hairspring once again. I disassembled the entire movement and thuroughly cleaned it -- twice -- oiled, and reasembled it. There are no bent or broken pinions. The only other damage was a sheered-off screw head attaching the ratchet wheel to the mainsrping barrel, but a little fiddling with the tweezers worked it out and I fortunately had an extra screw.

The problem now is that it won't run more than a few ticks before stopping. After doing a little research I think that the hairspring might be out of beat (could be wrong, but it seems that is at least a primary problem... I'm sure there are others). Since the hairpsring was so twisted to begin with, I'm not sure where the stud was supposed to sit in relation to the balance cock and the roller jewel below. The outer coil may need a slight adjustment to bring in inward or outward. So where should the stud be when the balance wheel is at rest/not set in the balance cock? If anyone has a photo it would be greatly appreciated, or even just a descriptive reference (lined up with this and that, etc.) I do realize I could replace the hairspring, but I wouldn't know how to set the new one without knowing where the stud sits.

Sorry if this is a newb question...

Thanks,
-Maegan

 

[Skutt50]

Try the following:

Release all tension from the main spring so the escape wheel does not move at all when the balance wheel turns.

Then bring out your strong magnifier and look closely to make sure the pallet lever sits in the middle between the banking pins when everything is at rest. That should give you a beat that is close enough for the movement to run.

If you are much out of beat you can also hear this when the movement runs. The tic tac should be even. When out of beat you hear tick........tactic.......tactic.....

If the pallet lever is not centered you have to turn the collet at the balance arbor.

 

[johndmc]

Once you are satisfied that the watch is in beat. You may want to mark the stud position on the balance wheel, if it is not already marked. After removing hairspring distortions, I usually remove the hairspring from the balance (carefully), and set the stud in the balance cock. This will allow you to see if 1. the hairspring is centered on the jewel settings, and 2. How flat and parallel the hairspring is to the balance cock. Breguet hairsprings are alot more fun and challenging, if that is the type. Good luck!!, John....... Of course this may mean that the watch might be out of beat again once the balance is reassembled.

 

[psfred]

The best advice I've ever gotten on this subject is to remove the hairspring from the balance (carefully!) and install the stud on the balance cock (or plate, some old watches have the hairspring stud installed there) and get the spring into the correct shape to exactly center the collet over the balance jewels, the correct coil set into the regulator pins, and the coil shaped exactly like the arc of the regulator when it moves (otherwise the beat is off when you move the regulator, to say nothing of erratic regulation!).

Once you have that done, mark the balance cock with a felt-tip marker exactly on the line between the balance jewels and the pallet lever jewels. Align the balance (you can just put it on top of the spring, no need to attempt to install it) so that the roller is perfectly in like with the mark you just made, and make another mark on the rim of the balance with your felt tip marker where the stud is.

You can then take the spring off the cock and flip the balance over and install the spring so the stud aligned with the mark, and you should be very close it in proper beat. It's also handy to make a different mark on the balance rim exactly in line with the roller jewel so that you can see when the balance sits centered in the pallet fork with no power on the watch, it's usually impossible to see the roller itself.

You should also check for recoil -- assemble and oil the watch but leave the balance and pallet fork out. When you wind a click of spring tension onto the mainspring, the train must instantly spin down, then stop and run backwards some. On 21 jewel (or higher) watches the recoil can be very large, on a 7 jewel I'd be happy if I got a couple revolutions of the escape wheel. More is better -- this is a measure of how freely the train runs. If you don't get free rotation, find out why (bent pivots, crud or corrosion on the wheel teeth or pinion leaves, old oil stuck to a jewel, etc). Note that stuck or improperly installed winding/setting works can cause problems here, also hands dragging or crud in the hour or minute wheel. If you don't have good recoil, you won't have good power transmission, and the watch won't run.

I've got a few 1920s Bulovas that will need some work beyond my current skills -- the train intermittantly locks on them, and I have not yet figured out why. I expect that I have excessively worn pivots somewhere, allowing the wheels to go out of upright, possibly the center wheel since it's not jeweled.

Another thing to check is proper escapement set up -- on watches with adjustable bankings run through ultrasonic cleaners you may have the banking pins rotate while being cleaned, and this will screw up the escapment, notably pallet stone locking. You should set the escapement up properly (do a web search, there are good references out there).

Loose pallet stones are also a possibility, shellac does actually eventually degrade with age, allowing them to come loose. Ultrasonic cleaning again will not help that much.

Persevere -- this is a great learning experience!

Peter

 

[Cymorill]

Wow, thanks for all the wonderful advice! I hadn't thought of taking the hairspring off the balance arbor to check that it lined up with the jeweling... I just fiddled with it until the spring looked centered when assembeled. My horologist showed me how to pop a hairspring off, but I haven't worked up the nerve to try it myself yet. I guess now is a good time! That little spring was pretty bent out of shape, but I'm actually enjoying the hours of fine-tuning to get it just right.

I'll check the recoil of the train, too. Before assembling the escapement I did give the mainspring barrel a little nudge to make sure everything was spinning freely, but not by windng the spring. I give that a go. This is only a 7j watch.

I can see the roller jewel from the top of the balance as a small red dot where it's set. The pallet stones look to be in good shape; before I cleaned the parts in Naptha the stones had a coating of green goo that needed gentle brushing off with a stiff paintbrush.

For future reference should this issue come up again, is it better to work the kinks and bends out of the hairspring while it is still on the ballance arbor and then do the final adjustments off, or just take the whole thing off to start with?


Thanks again,
-Maegan

 

[Cymorill]

I spent a few hours tinkering with the hairspring today. The watch is now running steadily so long as I leave it positioned upright, but when I lay it flat on it's back it stops, or on its face it starts and stops intermittently and seems a bit slugish. Time-wise it has lost about 2 mintues in the last 1 1/2 hours, but at least it hasn't stalled. This a marked improvement, though of course still far from "running" condition, but is very encouraging. This is probably the first time this watch has run in 30+ years.

 

[Skutt50]

So you need to first check very closely that the hairspring moves freely and does not interfere with any part of the movement or the arms of the balance wheel.

If you can not find any problem there I would remove the hairspring and fork and install only the balance wheel to make sure the balance turns freely in all positions.

If it does your problem may with the fork/roller interaction or indeed the hairspring.

 

[Cymorill]

I appreciate the tips and suggestions; I'm still very much a novice at this.

The hairspring does seem to be moving freely, but it's difficult to see from all angles. I don't think the stud is quite aligned as it should be. Because the hairspring was so mangled, I don't know what it should have looked like other than the obvious overcoil (Breguet). I trying to search Elgin Breguet hairsprings in Google, I found a thread here on the NAWCC board that mentioned Elgin frequently used the D-shaped overcoil? Perhaps that had something to do with it as the spring doesn't seem long enough for the stud to be in beat without the outer coil coming in very close. When the balance wheel stops, even just a very slight touch starts it going again. It's about 13 minutes behind now over 5 hours, but it hasn't stopped.

I might clean the pallet fork and jewels again, as they were very dirty. When the balance wheel does stop, it doesn't always do so suddenly; sometimes it stops and then slowly edges to one side as the escape wheel pushes on one of the pallet jewels, but the wheel tooth doesn't clear the jewel... Could the end of the jewel be a little gummy still? It looks alright.

 

[Skutt50]

You could do a simple check of the geartrain by removing the balance wheel and the fork. When you give the mainspring a one click wind the escape wheel should spinn to stop and then reverse a little. If it does, you install the fork (no oil) and make sure it falls from one side to the other when you turn the watch. Now it is time for troubbleshooting the balance part!

From your description it sounds like the balance wheel is touch something in certain positions. Is the balance wheel really centered and properly shaped? Could it be a timing screw that is too far unscrewed? Could it bee that the hairspring does interact with the balance wheel at some point? Good magnifiers and patience required!

 

[RJSoftware]

First thing, is this a flat style hairspring or does it have an over coil. To tell which kind your suppose to have examine the regulator on the underside of the balance cock.

Flat spring regulators are usually like a loop, but has a screw end that you can turn so to open the loop and remove the hairspring.

Over coil (brueget) is definite and has a regulator that is just two pins pointing down that the hairspring fits between.

So you might have to reshape if you picked the wrong style.

To bend an overcoil I use a small sewing needle that I ground the eye off of so that it resembles a 2 pronged fork. Grind the 2 prongs so that not much is left. Then find some corkboard or thin rubber mat. With the hairspring coils perfectly round and laying flat on the matt, pick your spot to have first bend to raise the coil. Press straight down with 2 prong fork on that spot and the rubber/cork will give enough so that the hairspring bends upward. Do a small test bend first so to get the feel for how much. Then flip the hairspring over and bend the next bend as near close to the first as you can get or about little less than 1/8th inch from first bend. Press till you think that the coil is parallel with the others. This is an offset bend to start the over coil. The distance between the two levels should only be about hairspring thickness between the two. So if you mess up first time, don't worry it happens till you get the hang of it. Just take time and bend back on flat edges with wide tweezer. Usually it's the second bend that gives me the buisness.

Once you have the offset bends correct then you begin turning the coil inward at a more sharp coil than the body coils. Use a peice of paper and have drawn lines and center mark so to indicate the travelling arc of the regulator loop. The inward coiling should aim for there.

Whatever you do, don't cut any hs length, no matter what. If you wind up with any excess it is most likely wrong, but, it may appear correct. The watch probably left the factory with that hairspring and it was perfectly vibrated to mate with that balance wheel. Vibrating is basically where the hs is selected accourding to the specific size and individual weight of the balance wheel and the hs cut to length based on it's performance compared to an already established balance of simular beat per hour.

Another consideration is that no coil should touch another coil. If it does then it is the same as shortening the coil at the point of the contact.

The coils should be "true in the round" meaning equal distance throughout and circular. Not tight at one side and wide at the other. Often an improper regulation loop offset/bend puts pressure on one side of the coil. Also "true in the flat" which is the body (not overcoil) coils are perfectly even when viewing from side.

Sounds too like you need to get a good set of tweezers instead of the pointy pliars.

As to your problem, as you now describe it, my guess is either your hs is rubbing balance arms or under balance cock plate. This is often due to too much distance between the hs body coil level and the hs over coil level. The overcoil should just skim over the body of the coil. No more than a hs thickness in distance between levels. Also, if the overcoil is not parallel (hard to do perfect) then it bends the coil body or overcoil and rubs against something.

 

[Cymorill]

You could do a simple check of the geartrain by removing the balance wheel and the fork. When you give the mainspring a one click wind the escape wheel should spinn to stop and then reverse a little. If it does, you install the fork (no oil) and make sure it falls from one side to the other when you turn the watch. Now it is time for troubbleshooting the balance part!

I did this and it does spin freely, but does not reverse at all just slows to a stop. But the click wheel might not allow the mainspring barrel to go backward. It is only a 7j movement.

From your description it sounds like the balance wheel is touch something in certain positions.

The spring might have been just touching the ends of the regulator pins... it was lying flat, but slightly elevated from the collet if that makes any sense. A little more fiddling today and now the spring slides easily between the pins (instead of me having ot guide it with tweezers) and the stud fits in easily. The fork is centered at rest, too. I wound it and it's running strong in all positions, but it hasn't been running long enough to check for accuracy.

First thing, is this a flat style hairspring or does it have an over coil. To tell which kind your suppose to have examine the regulator on the underside of the balance cock.

It seemed fairly evident that is was an overcoil-type hairspring when I first looked at it. The height of the stud hole and the position of it in the balance cock suggested that either it had a raised overcoil or the hairspring should have been half the size it was when coiled.

To bend an overcoil I use a small sewing needle that I ground the eye off of so that it resembles a 2 pronged fork....

That's a great idea for a tool! It may have been easier with something like that when I'd started.

... The distance between the two levels should only be about hairspring thickness between the two....

That's extremely helpful!

... Whatever you do, don't cut any hs length, no matter what....

Oh, no no no no no no! Never! That'd be like having parts left over, and that's always a bad sign!

The coils should be "true in the round" meaning equal distance throughout and circular. Not tight at one side and wide at the other. Often an improper regulation loop offset/bend puts pressure on one side of the coil. Also "true in the flat" which is the body (not overcoil) coils are perfectly even when viewing from side.

Have spent many hours making sure they are perfectly even and round.

Sounds too like you need to get a good set of tweezers instead of the pointy pliars.

I'm not using pliers at all, only a pair of very fine-tipped tweezers.

As to your problem, as you now describe it, my guess is either your hs is rubbing balance arms or under balance cock plate. This is often due to too much distance between the hs body coil level and the hs over coil level. The overcoil should just skim over the body of the coil. No more than a hs thickness in distance between levels. Also, if the overcoil is not parallel (hard to do perfect) then it bends the coil body or overcoil and rubs against something.

The overcoil was a little high and when it was set in the balance cock, the far end of the overcoil was pushing down on the body of the hairspring ever-so-slightly and causing it to just touch the ends of the regulator pins. Your point of the space between the overcoil and hairspring was very helpful.

 

[Skutt50]

I did this and it does spin freely, but does not reverse at all just slows to a stop. But the click wheel might not allow the mainspring barrel to go backward. It is only a 7j movement.

You might be OK as is but even a 7 jewel gear train will reverse the escape wheel. The click will lock one end of the mainspring and the other end will force the gear train forward. When the mainspring is fully let down the spinning wheels will continue spinning and will "wind" the mainspring backwards. It is this backwards wind that will reverse the escape wheel when released. (On some very smooth movements there may even be a second turn where the escape wheel moves forward again before it stops.)

 

[Cymorill]

I didn't realize the momentum of the gear train should have enough energy to force the mainspring forward... it doesn't appear to spin that fast.

 

[RJSoftware]

The momentum he is reffering to is the ultimate test to tell if your train is freely spinning with no errors.

Think of the bit of back spinning sorta like a diving board bouncing back up after the diver jumps off. The mainspring coils actually flex out a bit past relax and the gear train turns opposite direction (in a really free of error train).

Another test is to install the balance without the hairspring at all. The balance wheel (when pivots are perfect and power of the time train correct) will bounce off the banking pins back and forth and keep going like that.

The former test is really more for when you cut pivots on a staff that you turn. But, it also is good indicator that there is ample power in the train.

 

[Cymorill]

I think there may be some hidden about of gunk somewhere and I may need to tear the whole thing down again.... The watch ran happily ticking away all evening while it was sittin beside me on the table under a reading light (hallogen), but when left on the finrplace mantel it seemed to have stoped around 1:00am. It was very cold last night. It didn't want to start again on its own despite a little coaxing so I thought I'd try something: I set it on a sunny windowsill. After a few minutes it started ticking again and, having been left there all day, kept running and it keeping reasonable time. Sounds like dirt somewhere to me.... maybe some old oil that didn't quite come off. It looks clean, even under magnification, but perhaps there's some small bit in there somewhere.

 

[psfred]

Ancient "natural" oil can turn into a substance similar to shellac that will not dissolve very well. Same thing can happen to the oil on the mainspring -- very old natural oils become quite gummy and will glue the coils of the mainspring so tightly that the watch will not run as no power is being transmitted. Much worse cold than warm, too. A rinse in cleaning solvent will usually not remove this stuff, it has to be scraped off. Gummy grease on a mainspring may take several attempts to get it all off -- saturate a small bit of lintless cloth with naphtha or lighter fluid and pull the spring through the fold, holding it in a pair of tweezers. Repeat with clean cloth and repeat until the cloth stays clean. You should lubricate the spring by pulling it through a bit of folded lintless cloth saturated with an appropriate mainspring grease (Moebius D5 for instance). You want only a thin film of lubricant, not enough to stick the coils together.

Petrified oil on the jewels or bushings must be removed with pegwood, sharpened to fit into the holes. It won't come off otherwise, and will add considerable friction to the train, even with fresh oil applied.

What are you using for oil? Most 7 jewel watches won't run well at all until properly oiled, too much friction.

Peter

 

[emso]

i would look for endshakes.


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emso