Cracking a Breitling.

Some time ago a customer brought in a Breitling automatic chronograph for a service. If you are at all familiar with Breitling, you will know that the case back is designed specifically to make life difficult for anyone to remove without special tooling. I have a few ways of getting them off if they aren't cinched down too tight, but this one was extremely tight.

Breitling do not have an authorized service center in New Zealand. The customer didn't want it sent overseas, and frankly, I don't see why he should have to, so I said "Leave it with me...." and I got my thinking cap on. A bit of careful measuring, and a bit of light CAD, and I had a solution. This was going to be extremely time consuming, but I reasoned that I was bound to see a few more of this case-back, and the tool would be useful in the future...... So far I think it has only been used the once, but I do get to pull it out of the draw occasionally to show people... so that's nice. In retrospect I think I could have bought a whole set of aftermarket Breitling openers, but they're pretty darned expensive.

Anyway, I figured I could use the handle from my Rolex case opener and just make a fitting for it, so here is how I went about it. Breitling have an uneven number of flat steps around the case back, which makes it difficult to even measure accurately. I used the vernier caliper to measure around the outside of the steps. I then drew a circle of that diameter in CAD, divided that circle into five segments, drew lines joining the outside of each segment (creating a pentagon) and then drew another circle intersecting the middle of each side of the pentagon. This (hopefully) gave me the pitch circle for drilling the pin holes. Have I lost you yet? Luckily for me about the only bit of maths I was any good at was geometry. Something about being able to visualize it....

Test fitting... not quite there yet.

These stainless pins needed to have flats milled in them. It was really just a matter of taking a tiny bit at a time out, ane then re-checking.

So there we go. One Breitling chronograph opened to reveal a Valjoux 7750 movement, which was duly serviced and returned to a happy customer.

Cheers all.
Blair.