Balance wheel spins and then stops

[Hank7421]

I'm looking for some suggestions. I took apart an Elgin P.W. Model 2 1905 0s Grade 318 15j movement, cleaned it, oiled it and replaced the mainspring which was badly set. I installed it in a nice Hunter case. With the crown pulled out I can see the center post rotating as I turn the crown. However, when I pushed the crown in and wound it up and blew a puff of air on the balance wheel it spun beautifully back and forth but would not keep going. It continuously stopped after about 20 seconds. Any suggestions on what I should look for?....Hank

[chaplin37]

sounds like you have to put the watch in beat. If you have to use air or shake it a little bit to get the balance wheel to start running then it is a beat issue.

[SteveFitzwater]

ok, it could be the roller table is not aligned properly, thus not allowing the watch to be in beat... disassemble as much as needed to be able to see the roller jewel, and the post for the pallet fork, the roller should line up in the middle of the two pallet fork posts, if it does not( and I am assuming the pallet post have not been adjusted), simply place a small screw driver into the roller table seam and carefully rotate to the side that it needs to be adjusted to.. this is very touchy work, it is in Bob's watch repair videos on how to adjust and what your looking for.

The closer you get it to centered, the better the watch will run and more accurate it will be. The Balance cock MUST be installed and the hairspring attached so you get the true resting position of the roller jewel.

Here is a picture of a misaligned roller jewel.. click on the picture, it will go to full size and you can move it and zoom in as needed. The picture had such a short focal range, but if you see the pink/purple, that is the roller jewel on the first picture, it is on the right side of the posts, thus not in beat.

https://goo.gl/photos/ByGP5bjEuVswympQ7

and here it is after I have adjusted it

https://goo.gl/photos/MNzorSBNjMxTNDoB6

[Arutha]

If you have not already I would take the balance and the pallets out and just check the power is getting through the train ok. A couple of winds and see if the escape wheel stops and reverses.
If this is all ok then start looking at the escapement.
Paul.

[Hank7421]

I looked through the balance wheel and the roller table post seems to be very close to center between the two posts. However, when I watched the balance wheel oscillate back and forth I saw the pallet fork moving back and forth but the escape wheel was not moving even though I wound it a number of turns and I could feel the pressure of the mainspring.

[SteveFitzwater]

Did you try what Arthua recommended, what this test shows if there is any form of drag in the train, remove the balance and pallet, then give the mainspring ONE single turn, what you SHOULD see is the train spinning, then when the power runs out, the escape wheel should turn backwards a little bit. What this shows it the momentum of the train is free enough to transfer some power to the mainspring (not much, but enough to cause the escape wheel to spin in reverse just a little bit. If the train does not spin freely, or you do not see the reverse spinning of the escape wheel, it means you have friction some where between the escape wheel and the mainspring.

So what you need to do is run the test Arthua recommended, then based on your findings either reinstall the escapement or disassemble the watch and reinspect each pinion and jewel.

[Hank7421]

That was some really great advice and it is my next step. I will let you all know how that turns out. I appreciate all of your helpful advice. I love restoring old pocket watches but I have to admit that at times I feel like pulling my hair out. It can be quite frustrating because each manufacturer puts their watches together a little different and sometimes I simply have no idea if I have it right or not. If any of you could recommend where I could find a publication that would give me this information in the form of pictures or drawings it would be extremely helpful. I'm always interested in video or on line courses that would further teach me about pocket watches, so if you come across good ones please pass it along to me. Until then, I rely heavily on help from you more experienced Horologists. Thanks, if it weren't for you guys, I would be completely bald by now.

[Hank7421]

Ok, here's what I found. I removed the Balance and the the pallet fork and gave the mainspring a few turns. The gear train did not move. I tried moving the escape wheel but it seemed jammed. After letting down the mainspring I could move the escape wheel and all the gear train moved easily.

[Arutha]

Hi Hank,
remove one wheel at a time and try again until you find the problem wheel. You could have a bent pivot/bent arbor/cracked jewel/worn jewel/worn plain bushing.
The first job is to find the main cause so removing one wheel at a time starting at the escape wheel until it starts spinning freely. A common cause can be a worn centre bushing if it is plain and not jeweled. Also loss of end shake on one of the wheels if a cock or bridge is bent, maybe check that first?
Paul.

[SteveFitzwater]

so to help with the disassembly and reassembly of the pocket watches, use your phone (almost all smart phones have a camera), take a lot of pictures, to get them from your phone to you PC, you can use google photo's and link your phone to it, it will automatically up load the images to it and then you can access the photos on your PC (bigger screen) when your ready to reassemble.

Follows Arutha's advice, what your looking to find is either a bent pivot, cracked jewel, or a worn out pivot hole, since your seeing binding when power is applied, it means the alignment of the train is changing, thus binding the train up and stopping the pocket watch from running.

[Hank7421]

Ok, sounds good. I will start the process. Thanks for giving me a direction to go in and something to look for.