Hamilton 912 restoration issues

[Federico]

Greetings to you all. I have been restoring my Hamilton 912 pocket watch using some part movements. I have replaced all the jewels, installed new mainspring and installed a new hairspring.

 

I have been having trouble getting the watch to start.

 

The mainspring is pushing power through the entire train with the pallet fork removed, but for some reason it is not starting the balance.

 

Any ideas?

 

 

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[rodabod]

Assuming the train is driving all the way through to the escape wheel with enough torque, you will need to investigate the action of the locking/unlocking of the pallets by flicking the lever left and right. You need to inspect it with an eyeglass. There are references online and in watchmaking books about how the lever escapement should operate, so I won't repeat that here.

If the pallets are locking/unlocking correctly, then inspect the balance. Does the impulse jewel look ok? Check the balance can swing freely, and if you need to, remove the pallets to demonstrate that the balance will oscillate freely without stopping suddenly. With the balance fitted, check the safety roller action: can the balance rotate through the "lift angle" without the guard pin fouling the safety roller?

[Federico]

Assuming the train is driving all the way through to the escape wheel with enough torque, you will need to investigate the action of the locking/unlocking of the pallets by flicking the lever left and right. You need to inspect it with an eyeglass. There are references online and in watchmaking books about how the lever escapement should operate, so I won't repeat that here.

If the pallets are locking/unlocking correctly, then inspect the balance. Does the impulse jewel look ok? Check the balance can swing freely, and if you need to, remove the pallets to demonstrate that the balance will oscillate freely without stopping suddenly. With the balance fitted, check the safety roller action: can the balance rotate through the "lift angle" without the guard pin fouling the safety roller?

 

The impulse jewel was loose but don't think that will solve this. Will fix that as soon as I can get my hands on a roller remover to properly fix it.

 

The balance moves nicely till it comes in contact with the pallet fork perhaps the guard pin is causing some sort of friction? Too high too low? Don't know will have to examine somehow.. if the guard pin is too high do I just move the roller table up on the balance staff?

 

Been working on this one for the last two weeks now for about 5 hours a day before I decided to ask for help, but it is kinda driving me crazy now.

 

I have a copy of De Carle's Practical Watch Repairing and the John Tope's Watch Repairing course. I need to get myself a copy of Fried's book I just wish it was available in digital form. I highly dislike having physical books..

 

Thanks for the help!

 

 

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[rodabod]

Physical books are the best! I'm glad you like digital ones. 

It's difficult to inspect the safety roller operation. Sounds like you need to try and establish what the issue with the guard pin is, if there is indeed a problem. They can be bent, too long, etc. A loose impulse jewel will not help matters as it may lead the safety roller to be out-of-synch with the guard pin, if that makes sense.

[Federico]

Physical books are the best! I'm glad you like digital ones. 
It's difficult to inspect the safety roller operation. Sounds like you need to try and establish what the issue with the guard pin is, if there is indeed a problem. They can be bent, too long, etc. A loose impulse jewel will not help matters as it may lead the safety roller to be out-of-synch with the guard pin, if that makes sense.

Yea. Physical books just take up too much space for me, but it seems with this special book I will have no other choice. Will take a closer look at the guard pin this weekend after I fix the roller jewel. There have been a great many issues I have had with this little movement trying to use the best condition gears, jewels, etc. it has been hectic. With this process I discovered that the movements are not even 90% identical the gears and jewels all have various sizes that can be dramatically different from one another. but it has been a good learning experience. Will follow up with my findings this weekend. I kinda need a break for a couple days. It has been a tiring two weeks. I swear I even dream about the possibilities of why it is not ticking... hopefully fresh eyes will do some good.


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[Federico]

Well it seems I might have figured out what was going on with this. Firstly I took a closer look at the jewels on the balance cock and on the plate. The plate was fine the balance cock was just ever so slightly out of alignment. Once that was fixed the balance started rotating much better. After running some tests I began to notice a small tick sound which I discovered to be the balance ever so slightly rubbing on the pallet fork plate. So I fixed the balance arms so they where no longer rubbing on the plate. Re seating the roller jewel proved to be a very tedious task that I have not yet accomplished. I am awaiting a special tweezer that I hope will allow me to install the roller jewel with more precision. Will update next week.


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[matabog]

Sorry!  What does that special tweezer look like?

B

[Federico]

Sorry!  What does that special tweezer look like?
B

It is a no. 5 presto tweezer. See attached:



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[jdrichard]

Where did you get the new hairspring


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[Federico]

Where did you get the new hairspring


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casker.com


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[jdrichard]

Thanks

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