Case back opening tool / options for a Breitling Chronospace Military

[neilma]

Hey folks

I need to remove the back from my Chronospace to change the battery but I have stumbled at the first hurdle.

I've tried many options but wondered if anyone else had any ideas?

1. Tried blue tac - No movement
2. Bought a cheap set of dies from Amazon - None of them fitted.
3. Have seen a couple of folks on Ebay that (I assume) make their own dies - Neither have the size I need)
4. Cousins dont seem to stock the size either.

Other than sending it off to Breitling, does anyone else have any other case back removal ideas (or even the right tool I could borrow - Happy to pay a deposit, return postage etc).

(for the record the case number is M78366 and I am measuring 39.2mm from one of the flat sides to the point opposite (its a 15 sided case back)

Thanks
Neil

[sickie]

Try the rubber ball case back opener, you can get them on eBay.

Even the Bergeon one's don't cost a fortune.


Sent from a technical device

[Bry1975]

You could 3D print a polygonal wrench or laser / water cut an aluminium 6061 wrench, also a dab of contact adhesive and wooden lever should work, use vinegar to remove the adhesive.

https://www.lasermaster.co.uk/product/easy-order/

[LondonNeil]

Try a squash ball if you have one, or buy a ball made for the job.

[walkerwek1958]

Try a squash ball if you have one, or buy a ball made for the job.

If the caseback is at all tight you're pissing in the wind trying this. One trick that does work, but it's a bit drastic, is to superglue a large diameter socket to the caseback, allow the glue to cure for 1 hr, then use a socket wrench to unscrew it. This worked for me on a old Omega that had been horrendously over-tightened many years ago, I broke Jaxa tool trying to remove it but the superglued socket did the trick. Nail varnish remover (Acetone) will soften the glue and allow the socket to be removed afterwards.

Provided the caseback seal is correctly seated and in good condition casebacks don't need overtightening to seal.

[Bry1975]

Neil,

If you can wait till new year I can have a posh 15 sided Poly wrench cnc milled.

[Normunds]

Try the rubber ball case back opener, you can get them on eBay.

Even the Bergeon one's don't cost a fortune.


Sent from a technical device

This.

And if caseback is really tight, it is good idea to put watch in movement holder, this provides better grip.

[Seiko7A38]

Neil,

If you can wait till new year I can have a posh 15 sided Poly wrench cnc milled.

Why go to the trouble ? They're available on eBay. (Not sure which size you'd need).

Edit: Cheaper direct from China: https://www.ebay.com/itm/355141047060

[neilma]

Thanks folks for the pointers. I have duly purchased the Bergeon Ball thingy. So I will try that.

I also remembered that I have a 3d printer :) And i've found a couple of dies on thingiverse that I can experiment with scaling up or down to see if one of those work

Else if those both fail, I will be in touch Bry - thanks for the offer of help!

And Seiko - Ive tried those - they dont fit unfortunately :(

Thx again
Neil

[neilma]

Just to close this off, thanks to some advice above, I played around with the 3d printer today and scaled up someones STL file on Thingiverse and got it to fit my watch :)

Case back opened, battery ordered and all good.

Merry christmas and a happy new year folks!

Neil