How many turns to fully wind cal285

river9 · Nov 28, 2022

Noob question. I own this cal 285 for a while and wear it from time to time (not frequently). Watch was serviced by skilled man lately (Sep 2022).

My cal 285 (case ref 14390-62-sc) needs at least 50 full turns before full wound, ie crown turning cannot wind main spring anymore.

It is common/normal? How many turns should I wind on cal 285? Thank you in advance.

Dan S · Nov 28, 2022

Turn the crown until you can’t turn it any more. There’s no need to count the turns.

river9 · Nov 28, 2022

Dan S
Urn the crown until you can’t turn it any more. There’s no need to count the turns.

Thank you @Dan S for quick reply.
I used to turn the crown much less with my others movements such as Certina 25-661, Seiko 6620....

Fulton8or · Nov 28, 2022

Check out Ranfft pink pages for additional technical data on various movements including your
Omega 285. Specs will include stem, balance and mainspring, as well as scans of the movements.
Check out the difference in mainspring barrel size between your 285 and the Certina.

river9 · Nov 28, 2022

Fulton8or
Check out Ranfft pink pages for additional technical data on various movements including your
Omega 285. Specs will include stem, balance and mainspring, as well as scans of the movements.
Check out the difference in mainspring barrel size between your 285 and the Certina.

Plelase for my education help me to 'decifer' these data (pics below).
I only need 20-25 turns to full wind Certina while on cal 285 I turn more times that that to reach the 'peak', ie I cannot wind anymore.
Note that crown diameters are roughly the same on both 285' Omega and 25-661 Certina.
Thanks in advance.

X350 XJR · Nov 29, 2022

You are comparing Granny Smiths to Golden Delicious.

Just because they are both hand wind movements doesn't mean anything other than just that.

JimInOz · Nov 29, 2022

river9
Plelase for my education help me to 'decifer' these data (pics below).
I only need 20-25 turns to full wind Certina while on cal 285 I turn more times that that to reach the 'peak', ie I cannot wind anymore.
Note that crown diameters are roughly the same on both 285' Omega and 25-661 Certina.
Thanks in advance.

The crown diameters are irrelevant, a revolution is a revolution.

If we look at the specifications of the two mainsprings we can see minor differences.

The Omega mainspring is taller, slightly thicker, shorter than the Certina and of a larger diameter (mainspring barrel) than the Certina.
The thickness usually indicates the strength, or stiffness of the spring.

So the Certina spring, being longer, would take more revolutions to wind into a smaller barrel, assuming that the gear ratios of both watches was absolutely identical, which is unlikely.

The only way to confirm "required number of revolutions" would be to measure both watches from dead flat using a graduated crown winder.

But I really wouldn't bother, just enjoy both watches.

Fulton8or · Nov 29, 2022

Take a look at timezonewatchschool.com\Illustrated Glossary of Watch Parts. From there look at diagrams 1) Movement top plate particularly crown wheel and ratchet wheel, 3) Keyless works including “Click here for more detail”, and 7) The Mainspring and Barrel. The various gear ratios involved with winding (crown pushed in), the length & strength of the mainspring and the diameter of the crown will determine the number of crown turns to full wind as well as the amount of effort needed to turn the crown.

river9 · Nov 29, 2022

JimInOz
The crown diameters are irrelevant, a revolution is a revolution.

If we look at the specifications of the two mainsprings we can see minor differences.

The Omega mainspring is taller, slightly thicker, shorter than the Certina and of a larger diameter (mainspring barrel) than the Certina.
The thickness usually indicates the strength, or stiffness of the spring.

So the Certina spring, being longer, would take more revolutions to wind into a smaller barrel, assuming that the gear ratios of both watches was absolutely identical, which is unlikely.

The only way to confirm "required number of revolutions" would be to measure both watches from dead flat using a graduated crown winder.

But I really wouldn't bother, just enjoy both watches.

Tks for your explanation on main spring spec reading.
Edit to add: after 10 hours of a "full wind" I need 20 turns to bring main spring to the same "stiffness" at the beginning

How many turns to fully wind cal285

river9

Dan S

river9

Fulton8or

river9

X350 XJR

JimInOz

Fulton8or

river9

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