Old fashion case back/ring openers

[Levine98]

Hi

One issue I continue to run into when restoring and repairing 1950s era Bulovas (and Gruens and Wittnauers) is how to properly open/close screw on (ring type) case backs. 

Did Bulova or others make a specific tool for this? If not, what generic tool do you use?

I've included two examples of the kind of case back I'm referring to. 

Any help is greatly appreciated. Levine98

[dadistic]

I've seen this style on Ebay, but I don't have any info on the sizes, etc.

I use a Jaxa style case back wrench to tighten the ring, but only after I've started it by hand. Too easy to cross thread otherwise. 

[Levine98]

4 minutes ago, dadistic said:

I've seen this style on Ebay, but I don't have any info on the sizes, etc.

I use a Jaxa style case back wrench to tighten the ring, but only after I've started it by hand. Too easy to cross thread otherwise. 

I have a jaxa style opener but the bits are too large for these rings. I've also seen the Bulova units you quote above, but like you there is no info on what size these things are used for

[oldhippy]

What I did and I had many back opening tools. A pair of old pliers and file the nose of the pliers to fit, make sure it is a good fit as you do not want to damage the back Hold the case in a vice if the have the Jaxa vice that will work fine. Open the pliers so the pliers fit in the slots and turn.