Balance Shaft replace question

[JohnTosto 1]

Hi All 

I have a follow up to a previous post, below is link to post.
https://www.watchrepairtalk.com/topic/14190-selecting-the-correct-balance-shaft/

With the help of JohnR725 I discovered that when ordering a replacement balance shaft you have to be careful as there can be more than one type/size per part number along with different pivots sizes.

Long story short I ordered the correct shaft (elgin 861 NS P.13) and was successful at disassemble, replacement, reassemble.

I have a couple of the same model pocket watches with at least same issue (bad balance shaft) can I replace an 861 NS P.13 with a 861 NS P.12 if I also replace the upper and lower balance jewels with P .12 size jewels?

Reason I ask is that I am finding the availability (at least currently) of 861 NS P.12 more abundant.

 

Regards

John

[JohnR725 1,359]

Elgin in any of their literature  doesn't seem to indicate whether there was a more common pivots size. I do have an assortment at work that the most popular pivots sizes were indicated. So it is possible that the 12 size pivot is the most common perhaps.

Then if you think the jewels are 13  size try the 12 size staff. You going to have a little too much side play but you might Be able to live with that. It's a bigger problem if it's the other way around the pivot is too big for the hole.

[saswatch88 156]

If you are comfortable replacing jewels then I suggest you do so, but try and get a couple size 13s you can check daveswatchparts.com