Job Number 210145
Getting ready to cut away the hub of the old staff...

I do the same thing every time a movement like this comes up; spend all afternoon researching the balance staff. Elgin documentation calls for staff part number 861 for many 16 size movements. But there is 861-c, 861 old style and 861 new style. If it needs an 861-c it usually, but not always, says so. If it just says 861 then it could be either new style or old style.

861 new style, or 861-NS, is a bit longer than old style (861-OS) at 5.32mm. Old style is, if I recall correctly, 5.17mm. These two otherwise look the same.

861-C has an oil groove. And it is also longer at 5.32mm. However the hub is a different size. It is not usually a replacement for 861-NS. It seems like I have seen them interchanged, but I could be wrong.

I found I have just one 861-NS staff on hand anymore, and it may be an after market part. It will need a little shaping of the pivots at any rate.

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