Hairspring attachment to stud 7S26

[tonydagee]

Hello all,

i was alarmed to find on reassembly when finally ready to install the balance that the hairspring separated from the stud, and no screw!

looking at an identical assembly from an additional 7s26 movement, it seems to be attached with… shellac?

is this right? I’m very confused! Please help!
tonyda G

[jdm]

8 minutes ago, tonydagee said:

looking at an identical assembly from an additional 7s26 movement, it seems to be attached with… shellac?

That is regularly asked, often by beginners which mishandle these delicate hairsprings, as in letting the balance wheel dwindle, etc.
The hairspring is glued with thermal synthetic product (not shellac) to the stud. Check well because if in fact has snapped, all bets are off.

[Nucejoe]

 Fill the stud slot with the glue/ epoxy/ nail polish, LEAVE THE ASSEMBLY COCK DOWN LIKE IN PICTURE YOU SHOW ABOVE UNTIL ITS CURED.  

Glue may  migrate and mess up the whole thing, so you want to use little glue just enough to fill the stud slot.

 Good luck.

[clockboy]

As JDM suspects the H/S has most likely broken off at the stud. A poor design for sure even if the stud is cleared of the old glue the original  H/S will effectively be to short. My advise is look for a replacement possibly from a donor movement. 
 

PS I speak from experience

[jdm]

4 minutes ago, clockboy said:

A poor design for sure even if the stud is cleared of the old glue the original  H/S will effectively be to short.

Possibly poor but it's the standard Etachron design, used on ETA mov.ts, as well on Seiko. I suppose it simplifies and makes production cheaper.

[tonydagee]

Well, I really did think my eyes were deceiving me! Nowhere a mention of that in any of the literature I read so far on my quest to establish watchrepair as a hobby. I learned something today. Thanks!