Longines Caliber 19.75 balance wheel repair

[Tschacko]

Guys,

I am trying to get my dads old pocket watch to run. Longines Caliber 19.75. I sense some problems with the balance staff. Could you have a look at the staff and balance spring.

I am thinking that the end of the staff is damaged and I am wondering if the balance spring is in its shape it should be. Where does the end curve begin and where do I need to adjust.

Any advice would be helpfull.

Thanks !

 

[nickelsilver]

The staff isn't original, it's a hokey homemade one. The upper pivot appears a bit sketchy, but who knows maybe it works? The spring doesn't look too bad. You can put it on the cock (install the stud in the cock) upside down and manipulate it so the collet is centered over the hole jewel, and get it parallel with the cock surface, then when you install it it will be very close to true.

[Tschacko]

2 minutes ago, nickelsilver said:

The staff isn't original, it's a hokey homemade one. The upper pivot appears a bit sketchy, but who knows maybe it works? The spring doesn't look too bad. You can put it on the cock (install the stud in the cock) upside down and manipulate it so the collet is centered over the hole jewel, and get it parallel with the cock surface, then when you install it it will be very close to true.

Yeah, the balance wheel isnt running when I put it in. How do you know that it is a homemade one? I just wanna learn. The original is a Ronda one

[nickelsilver]

2 minutes ago, Tschacko said:

Yeah, the balance wheel isnt running when I put it in. How do you know that it is a homemade one? I just wanna learn. The original is a Ronda one

 

The upper pivot is manky looking and malformed, the lower pivot is far too long and also malformed. A factory staff, especially for Longines, would have beautiful pivots that have identical lengths (total length with the conical section) and identical diameters.

[Tschacko]

3 minutes ago, nickelsilver said:

The upper pivot is manky looking and malformed, the lower pivot is far too long and also malformed. A factory staff, especially for Longines, would have beautiful pivots that have identical lengths (total length with the conical section) and identical diameters.

Yes, thank you that helps. I have a replacement (on the way to me) but I wonder if the jewel holes will be fitting or if the homemade one was replaced with the jewels. I guess I will know once it arrives.

I really never replaced a balance staff. I know in theory you can just do it with a staking tool. But you can also go the complicated route with weighing the balance wheel, having a tool for centering the balance wheel and so on.

I would need to buy a staking tool or just find a more sophisticated watchmaker in Germany. They are rare....

[JohnR725]

1 hour ago, Tschacko said:

I know in theory you can just do it with a staking tool.

To avoid unpleasant surprises you want to measure The old staff and verify that the new staff has the exact same measurements. Never assume that the replacement staff has the exact same dimensions even if it looks the same we really need a micrometer to do this. Although you do want to be careful with the pivots if you have a micrometer not the break them.

3 hours ago, Tschacko said:

I am wondering if the balance spring is in its shape it should be. Where does the end curve begin and where do I need to adjust.

Hairspring is out of the watch usually look fine. The problem is when they're in the watch so that's really the best place to have them to see if they look right.

 

[praezis]

2 hours ago, Tschacko said:

I really never replaced a balance staff. I know in theory you can just do it with a staking tool. 

Best way to damage the wheel, esp. if you are unexperienced.

2 hours ago, Tschacko said:

But you can also go the complicated route with weighing the balance wheel, having a tool for centering the balance wheel and so on

Will surely be needed if you "just do it with a staking tool", rarely needed if you do it the correct way.

2 hours ago, Tschacko said:

or just find a more sophisticated watchmaker in Germany. They are rare....

I would recommend this. Ask and find one who does more than changing batteries and straps. 

Frank

[Nucejoe]

Check this In case you haven't already, shows what master Nickelsilver advises.

I always thought of LONGINES as jewels, you may want to practice a lot on cheap pieces before you attack your watch.

Good luck