ETA 251.471 "fitting device"

[LittleWatchShop]

Another neighbor asked me to fix a couple of watches.

This one is the ETA movement in the title above.  It is a nice movement--23 jewel quartz chronograph.

All it needed was a battery.  However, I got curious about this movement and found the manual for it, and also watch a video of tear down and assembly.  Almost the entire train is under one plate and in the manual they say NOT TO attempt removal without a special "fitting device."

I am curious...what is this fitting device?

[Plato]

I think it refers to the magnetic rotor pinions and how they're pulled towards the stators whilst you're trying to fit the bridge. It's a bridge with 6 or so pinions to fit to it, if I remember correctly. Sounds tricky but the bridge is very thin and easy to fit, not a problem if you're used to mechanical watch repair. 

[Plato]

55 minutes ago, LittleWatchShop said:

I am curious...what is this fitting device?

I didn't answer the question, it must be some bit of plastic that lines all the pinions up before fitting the bridge. Probably! 

[Plato]

Replace pinions above with pivots (booze). 

[LittleWatchShop]

31 minutes ago, Plato said:

Replace pinions above with pivots (booze). 

I resemble that remark (booze)!

I bet you are right about the plastic guide.  The one quartz movement I have assembled (7 jewel) was really tricky because of the rotor wanting to snag on to the stator.  Now, I am itching to work on one of these but I will restrain myself!

Edited September 3, 2021 by LittleWatchShop

[jdm]

40 minutes ago, LittleWatchShop said:

The one quartz movement I have assembled (7 jewel) was really tricky because of the rotor wanting to snag on to the stator.

Exactly. There are tricks like sticking some iron under the rotor to keep it upright, but personally I have never tried that, and I'm not eager to. The sure way would be the factory jig mentioned in the service document (good luck even finding a picture of it), but once again my opinion is, if one can measure current drawn to be within specifications, just let an illusion of oil on the accessible pivots, and move on.

[LittleWatchShop]

1 hour ago, jdm said:

just let an illusion of oil on the accessible pivots, and move on

I'm on it!!

[HectorLooi]

Attempting to assemble a quartz movement without a "fitting device" will give you fits.

After watching one of Mark's videos on servicing a quartz movement, I stupidly attempted one. He made it look so simple.

I learnt a trick from somewhere in this forum to stick a screw to the underside of the plate so that the rotor will stay in its pivot hole. Works somewhat well but I came out with something better.

I made a movement holder out of an old strip of magnet and some ice cream sticks. It works so well that I never bothered to improve on it. I just used it last night. I swear that anyone can get the top plate fitted on in under a minute.

Maybe you could 3D print one and pay it forward by giving it to anyone who is tearing out their hair trying to fit a quartz movement back together.

[Plato]

9 hours ago, LittleWatchShop said:

I'm on it!!

I got all this lot as a pile of loose parts to practice on for less than £5, not sure modules by themselves would qualify for the 404 Club?

There were a load of faulty coils, some of which I salvaged with a blob of solder.