Adapter for Carl Zeiss Jenna Barrel Lens

[stp1974]

Hello everyone,

I am looking for some ideas on an adapter for this lens. It is glued into the metal block and I do not want to risk cutting it out. If you look at the second photo you will see that there is a 25mm (approx) female thread at the back of the barrel.

I was thinking of a C-Mount (25.4mm) tube maybe 10mm long and then a C-M42 cone adapter.

Anyone know I can accurately confirm the female thread dia. at the back of the barrel?

Thank you!