Horological Meandering

Hi, I own a project Breitling Chrono-Matic caliber 11 - the defective part is in the attached photo - regrettably, neither my watch repairer nor I know de name of this particular part - what little i know is that this part, a cylindrical wheel / gear, is that it joins the chrono function and the time function - hope someone can help me identify and source this part - thank u - Edwin

At least that is what is called functionally.  I'm not 100% that the part doesn't have a different name

A

Picture credit www.onthedash.com m

The Cal 11 was used by a number of companies, so you might be able to find a donor movement from another company. There is a rather well know Australian parts house that may have them
and the our favourite auction site.

I have done a bit of research - I understand part 8086 is also called an "oscillating pinion ('OP')" - apparently de OP in a cal.11 was bi-metallic ie. it was made of brass & steel, which caused it to wear down more rapidly, while that in a cal.11-I was made entirely of steel - I have de following queries - 1) I note de shape of de OPs from the 2 calibers are different, so that makes me wonder whether the OP from a cal.11-I is interchangeable with that from a cal.11. 2) what is de function of an OP? Does it operate only when de chronograph function runs? 3) how about de OP in a cal.12? Is it de same as that in a cal.11-I? 4) just wondering whether u could give me de contact details of de Australian parts supplier. Thank u. Edwin