i need help to identify this iwc caliber

Hi everybody!

I have one early IWC pocket watch movement with serial 118.267. The "DateYourIWC" program show me this is one IWC cal. 58 (Sav. c. 58 - 19lig. Mod. 1894) from year 1895. (this program based on the data published by Tölke-King)
But best of my knowledge this is not "americaine" movement. This movement similar to IWC cal. 55, just in savonette version. It is one IWC cal. 56 movement perhaps?
But the "DateYourIWC" program show me IWC cal. 56 largest serial number is 99300.
So what is the truth? It's cal. 56 or 58?

Best regards! Peter from Hungary

Hello Sternerp

It's an early version of a c.58, the savonette version of the c.55.
This copuple is also called calibre Schaffhausen.
Its someow confusing, the Lep. caliber 57 hat a Savonette version which was called in the beginning c.56. so there was initially two pairs c.55/c.58 and c.57/c.56 (lep/sav). The c.55/58 was not produced very long (1888-1895).
later, when te initial c.58 was not more produced, the Savonette-Sister of the c.57 got its correct number c.58. But this renumbering made a lot of confusions.

Here the daye your IWC is probably not correct, the 2 series 109'501-110'100 and 118'201-118'501 should be c.Schaffhausen c.58.
But the origin of this data had also a big number of wrong indications.

regards

Ralph

Hi Ralph!

Thank You very much for quik answer.

Little curiosity, i send 2 photos from my another cal. 55. It was common at the time this "high glossy" black dial? (I had never seen anything like it.)

Best regards! Peter from Hungary

Hello Peter

What is very special for your c.55 is the configuration for Breguet balance spring (it is not really in place ;-)
The c.55 was a cheap movement, normally with flat balance spring as found in the c.58 above.
I did nor knew it exist with Breguet spring.

The black dial hmm, it could be "not original", hard to say.
You could lift off the dial an see what is beyond...(feets set "manually")
Sometimes in the sales book special dials are indicated.

regards

Ralph

Hi Ralph!

I have 2 piece cal. 55 and one cal. 58, today i compare this 3 movement:

cal 58. sn: 118267 white dial, flat blued hairspring but compensated balance, (maybe this is original balance)

cal 55. sn: 119798 black dial, flat bright hairspring not compensated balance, (i think this not original balance and hairspring, the balance and hairspring is a bit bigger)

cal 55. sn: 119808 white dial, Breguet blued hairspring not compensated balance, but half sawn (maybe the balance is original)

All three movement balance bridge has marked under with the serial no last three digit. Has even one thing common this three movement, unfortunately none of them work ;-( Balance staff is broken.

The two cal 55 movement has so regulator key, which suggesting an Breguet hairspring.

I removed the black dial, and it seems to me that this is original.

Best regards! Peter

Hello Peter

The 118'267 ist a 19 lig. movement (you see the bigger distance of the at the winding wheels to the edge). It has a compensating balance but flat balance spring (bigger distance of the pins of the regulatong "device" and the attachment point of te spring to the center of the balance. This (118'201-118'500) is most probable the only 19 lig. serie of the Sav. c.Schaffhausen (c.56)

A compensating balance is to adjust failure to temperature; the Breguet balance Spring to correct position failure due to change of center of gravity of flat balance spring during oscillation. Theoretically they are independent of each other and can be present or not.
I think only this last serie (119'700-120'000) got a breguet spring on the c.55. The diamenet of this movement is, als all others c. Schaffhausen 18 lig. (Also here, there was only 1 Serie of c.55 19 lig. 114'301-114'900).
A bright balance spring (when original of this time) could be a non Magnetic one. The other balance springs where blueed steel.

119'808 should be identical to 119'789.

Regards

Ralph

Yes the dial seems to be original.

Hi Ralph!

Thank You for your help!

Best regards! Peter