Pre-Inca A. Schild: Which model and mainspring?

[AndrewSi]

I’ve got this thrift-store ladies’ watch movement that I’ve stripped down for practice. (Go easy on this newbie.). It’s got the A. Schild mark on the base plate but no model number.  Imported by Elaine Watch Co. and claims 15 jewels. Measures 10.5 lignes. I’ve put the bridges back in place in the photo to hopefully aid in ID’ing it.

The mainspring is ancient and distorted so I’d like to replace it (no backwards curve, pure spiral) but I can’t find an exact measurement match.  Width/strength wise my caliper tells me it’s 1.5mm x .14mm, or a Dennison 6/8, but lengthwise it’s only 10.5 inches.  Most of the springs that short in the catalogs seem to be a few steps weaker in strength and I’m not sure how that would affect its ability to run. Can someone suggest a best fit?

Thanks!

Edited March 5, 2023 by AndrewSi

[LittleWatchShop]

A. Schild 932 is my guess.  Can you take a picture of the dial side?

[AndrewSi]

Sure:

[LittleWatchShop]

Check here

[AndrewSi]

No exact match from the pics, but probably close. At least gives me some ideas for an alternate mainspring.

[Nucejoe]

Many variant of this caliber were produced, Dr ranfft lists them all in the webpage little watch shop showed. 

The keyless is THE SIGNATURE  of caliber, a caliber may have many different bridge layout.

 

[RichardHarris123]

Which type of bridle?

And the barrel diameter. 

 And the barrel diameter. 

[Neverenoughwatches]

3 hours ago, AndrewSi said:

I’ve got this thrift-store ladies’ watch movement that I’ve stripped down for practice. (Go easy on this newbie.). It’s got the A. Schild mark on the base plate but no model number.  Imported by Elaine Watch Co. and claims 15 jewels. Measures 10.5 lignes. I’ve put the bridges back in place in the photo to hopefully aid in ID’ing it.

The mainspring is ancient and distorted so I’d like to replace it (no backwards curve, pure spiral) but I can’t find an exact measurement match.  Width/strength wise my caliper tells me it’s 1.5mm x .14mm, or a Dennison 6/8, but lengthwise it’s only 10.5 inches.  Most of the springs that short in the catalogs seem to be a few steps weaker in strength and I’m not sure how that would affect its ability to run. Can someone suggest a best fit?

Thanks!

It is possible to have a different length of mainspring fitted, but better to establish what its original size should be as the one you are measuring may not be the original. For this we need to identify the movement. Some individual components of the keyless works such as the setting lever, setting lever spring , set bridge ( sometimes called the jumper , setting lever jumper ) and the yoke. These can help to identify the  calibre of the movement ( the movements fingerprints). All of these components may not apply and there isn't always a reference available depending how old or how rare the watch is. But its always worth a try.