medana Medana pocket watch - broken hairspring

[Tr0phy]

Hello, 

I got this vintage medana pocket watch with MST 12 movement. When I opened them I saw broken hairspring.

What should I do ? I´m very new to these watches, I need some help/advice.

[rodabod]

Possibly easiest to acquire another movement. 

[SeikoWatch]

hmmm... not necessaryly Rodabod.. a broken hair-spring can be changed for those who know how to do .

[SeikoWatch]

Tr0phy , If you are comfortable changing the hairspring, no worries. If you're a newbie, bring the watch to a watchmaker and ask how much it would cost to change a hairspring It is more difficult to change the part yourself than to remove a screw or to change a wheel because a hairspring is very fragile and is easily twisted if you pay no attention.. Once done, you just have to put everything in the watch .

[oldhippy]

To start with it is not a compensated balance, I cannot tell by the pictures but I have a feeling it could be a cylinder escapement. Even with a donor movement the hairspring still might not match, the balance complete would be the answer.   

[szbalogh]

If no replacement balance then the hard way.... get a stock HS then measure the vibration and cut to length and finally mount to stud. For a cylinder escapement it is not overcoiled so not that hard.

[oldhippy]

2 hours ago, szbalogh said:

If no replacement balance then the hard way.... get a stock HS then measure the vibration and cut to length and finally mount to stud. For a cylinder escapement it is not overcoiled so not that hard.

I suppose you think the old hairspring collet can be used?

[szbalogh]

Just now, oldhippy said:

I suppose you think the old hairspring collet can be used?

Yes the collet. If one can replace the HS on the collet then fine... maybe in case of bigger watches. 

As i was browsing around it seems to me that stock HS comes collet-mounted. Or not? I am just guessing. 

Since the HS is mounted on the collet like on the stud, theoretically it can be replaced. Never had to do this but there is a description about this topic in DeCarle's books. 

[oldhippy]

I'm not knocking DeCarle books but it is a hell of a lot harder achieving this task then just reading it from a book. An experienced watch repairer would find it hard, if the collet gets damaged then finding one that fits will be very hard indeed, after all it has to be the right size, height and width.    

[Marc]

7 hours ago, oldhippy said:

I cannot tell by the pictures but I have a feeling it could be a cylinder escapement

OH is absolutely right, this is a cylinder escapement. If you look at the rim of the balance wheel just past the 12 0'clock position you can see that there is a little stud poking out of it. Cylinder escapements have to limit the amplitude of the balance wheel to <180 degrees and this is achieved by having a pin underneath the balance cock which sits very close to the balance wheel rim, and a stud on the rim which can't get past the pin.

As far as getting a balance complete from a donor watch is concerned I think that this is going to be something of a wild goose chase. Even if you manage to correctly identify the movement, and manage to find a correctly identified donor, and the cylinder, HS, and pivots are still in good order, the likelihood of it fitting and working is very small. These watches would almost certainly have had a degree of hand fitting done at the manufacturing stage resulting in no two watches being exactly alike. If you are lucky enough to find one that just drops in and works..... buy a lottery ticket

Vibrating a new HS is your best bet for a successful outcome but as OH says, this is a technically advanced and somewhat fiddly exercise. Still if you don't try you'll never advance, so I'd give it a go.

Good luck.