I'm working on a Seth Thomas 18s , model #5, Grade#182 that had a bunch of issues when I bought it. Broken mainspring,no whip spring, bad hair spring & staff. It's running fine & keeping time. Unfortunately it still has a couple of issues and I need your help. The watch stops when I tighten up the balance cock screw. It works fine when I press on the balance cock & does so in all positions. Here is a photo of what I mean. Any help would be much appreciated. Tim Fitz
When I do a staff I always test fit it before staking it to the balance. I clean and oil both sets of jewels and carefully put the staff in place. Gently tighten the cock screw while checking for free spin of the staff. End shake is easy to check now too. I Also check for pigs ears under the balance cock and on the plate under the balance cock made by a previous "watchmaker". These should be removed carefully. After staking the staff to the balance I install it again checking for free spin in all positions and endshake again. Very unlikely that the balance cock is bent unless someone bent it in an effort to adjust endshake one way or the other. Yes, unfortunately it is done. That's my procedure, YMMV. Roger
Good advise, I will add that I use a marking pen on the side of the staff so I can see it when I turn it with a tooth pick or any other tool. If you are turning it and it doesn't have any resistance, you know when you stake it to the wheel it will turn freely.
I think it's just a shadow. After zooming in as far as I could it looks allot better, lol I thought the same thing at first.
There is some roller jewel extending out the other end and you might be able to still use it if you push it through a bit, after heating to soften the shellac.
Yes, I was able to move the jewel up a bit.Still it only runs when pressing down where I showed in the picture. I'm stumped. For Now
To mee is sounds like the balance cock is not sitting flat agaings the main plate! There must be some pig ears or similar, causing the cock to tilt slightly when you press on the back side. Perhaps one of the guiding pins does not go down all the way into the plate. Just make sure it is not deep enough to touch the safety pin in the pallet fork. Could it perhaps be turned upside down?
I tried a little experiment, I placed a tiny bit of masking tape under the balance cock as close to the edge as possible I tried three layers then two and when It was one, it worked fine , in all positions . I took a photo of the piece of (Blur)tape I used, & placed it next to the balance to show it. What does this tell me? Thanks
Staff too long, jewels not set completely flat, or cock is slightly bent. That is what I would look at... I've had it happen on an old full plate 18s, and after removing and resetting the balance hole jewels it was perfect. These are just experiences I've had. Good luck with your project sir!
I can only assume you mean the inner edge of the balance cock. This would indicate that the balance end stones (for some reason) are too close together when the cock is screwed down, which in thurn stops the watch. In short: No end shake! If this is due to bent cock, pig ears, faulty balance or any other cause, that is the problem you need to figure out.....
Well I'm going to take it completely apart tomorrow and check everything even more closely. Perhaps the escape wheel or the pallet staff have an issue?
You never know what the people before you did to a watch, what parts they put in ,if they were correcting, inspect everything , if they installed them right. So I will start over and measure everything until I get it fixed..
You will find many of these old watches that have this done to get good endshake. If it’s your watch and it’s running well it may be best to leave it alone. Unless you have more staffs or jewels it can be a frustrating task to make well enough perfect. There is an article in one of the current AWCI magazines that shows a piece of stepped hardwood that was used in the Waltham factory to bend the cock to get proper endshake. You also may find yourself fixing it until you break it. Don’t ask me how I know that. Peter
A good clean is the best starting point when servicing a watch but if it works fine when you press on the cock, I don't think you will find problems with the rest of the movement. Did you check for endshake in the balance? Without some end shake the watch will simply not run!
Thanks everyone for your help & ideas! I Took it apart & checked everything, all ok. So my last hope was a bent balance bridge. Very carefully after removing the bridge I placed it on soft wood, gave it a lite tap with the brass hammer and found it was a little better. So after repeating the remove tap, remove tap five more times it is now running & keeping good time. I really was afraid to try it but worked up the courage & It worked out . As they say Slowly, slowly catchy monkey.
I’ll see if I can find it. It’s in one of the more recent issues of horological times. I think something written by Jack Kurdzionack .
Glad it worked! Taking a hammer to anything that has a jewel fitted in it is a bit bold though. You may find that you’ve made matters worse by cracking a jewel. Pressing is a more controlled and less violent process where you can even measure deflection should you wish. The best approach is to check where a possible bend is, before addressing it. Lay a straight edge on to of the balance cock as well as underneath it to check for deformation. If it is straight, you want to keep it that way. Grip the length of the balance cock in a vise with smooth an parallel jaws and then you can apply pressure to the mounting part of the cock. I guess this will come in handy for the next time you encounter this problem. Hope it helps! Regards Karl
Thanks I will keep that in mind. I didn't wack it with a hammer, I used a block of wood as a buffer.On both sides, and taped ever so lightly. Then after a few taps I remeasured.
Tim, this is from the December 2018 Horological Times. The answer to the question was in February or March issue. Right now I can’t find my copies. These were used in Waltham’s factory to adjust balance endshake. Peter
