Issue replacing crown Breitling Aeromarine

[NotAnotherWatch]

Hi all, having issue replacing crown on my Breitling Shark A13051.  Picked up a new Breitling crown assy on "the bay".  Removed old stem assy after careful heating with soldering iron.  The new crown appears to fit watch peferectly in all regards EXCEPT for winding stem tap size into the crown..... Should I use a die (pretty sure I have correct size) to turn down the stem to fit crown??? Or start over???? Any thoughts??? Thanks!!!

John W

[AndyGSi]

My first thought with buying off eBay is you've not got the correct part.

Not quite sure what you mean by crown assembly though?

Edit

So if it's a 7750 movement then it could be either a 0.9mm or 1.2mm Stem.

Have you got a crown gauge or calipers to measure at least the stem?

[NotAnotherWatch]

Yes it's a 7750.... it would appear that I obviously have the 1.2 stem and the .9 crown assy.  I do have very good calipers and very well may have the dies Ness to thread down the stem.....   I'm debating whether to go that far or just source correct crown asssy (spring loaded screw down, poor design IMHO).......  IIRC there were some quartz Breitling Aeromarine with same designation and I wondered if I ended up with one of those crowns.....   I do believe if will work fine it I turn it down to proper thread pitch.....   But debating the trouble is finding correct part!!

Thx!   John W

[AndyGSi]

As you've already got the 0.9 Crown I'd just get a 0.9 Stem and give that a try first.

Do you have the Part No of the Crown you bought?

[NotAnotherWatch]

The part number it was sold under is 150.412.    Yes I will source other stem first.  Realized I was WAY over thinking this!!!!

Thx sir!!!! John

[AndyGSi]

OK so the crown should be a 150.423 for the A13051

Edit

You may find the 154.412 having a diameter of 6.4mm a little too big compared to the 5.8mm 150.423

Edited June 21 by AndyGSi