Reamer holder?

[caseback]

My mystery tool drawer holds something that looks like a reamer holder. It's diameter is smaller than the one from my Seitz jewelling set (6,3 vs 8mm). Does anyone know what brand staking set or jewelling set or ?? uses 6,3mm tools?

 

[watchweasol]

Hi could be from a favorite jeweling tool. I have one but not checked the holders . Probably worth doing sometime though.

[caseback]

13 minutes ago, watchweasol said:

Hi could be from a favorite jeweling tool. I have one but not checked the holders . Probably worth doing sometime though.

If you would: please.

 

I have a Favorite staking/jewelling set, but that uses 8 and 4,7mm tools. Yours might be different.