Longines 18.79 vs 18.79ABC vs 18.79z or any other modifications

[Dmitry]

Hello,

I am working on an older Longines, the plate states 18.79, but when I order a new center wheel and escape wheel, the new parts from 18.79 were a bit smaller and did not fit into my movement. Does anyone have any experience with 18.79 and clarify if there are specific variations that might have larger center wheel and a higher pivot on the escape wheel?

I am surprised the parts from another 18.79 did not fit. Is 18.79 ABC any larger? Ranfft has nothing on 18.79:(

Thank you.

 

[JohnR725]

11 minutes ago, Dmitry said:

older Longines

older like vintage? When was this watch made that you're trying to repair?

11 minutes ago, Dmitry said:

Ranfft has nothing on 18.79

one of the problems and watch repair is there a lot of watches out there. not just the quantity of watches like Seiko makes 1 trillion watches a year but the quantity of different styles grades models whatever from beginning of watchmaking until now there's a lot of. That means you won't necessarily find technical sheets service bulletins parts lists and if it's anything vintage then things become even more problematic.

for instance looking at American watches like Elgin for instance there is an 18 size balance staff you look up your watch you get a balance staff number you order it it won't fit. That's because it came in four different variations all the same part number and each of the variations had different pivots sizes. A lot of times this is documented other times it's not

then looks like your watches in the bestfit book.  but I'm afraid that may only add to the confusion as there's lots and lots of them.