Most of my vintage testers have those old style 5/8" screw on MIC
connectors. I have considered changing all of them to BNC and I see many
people do this, but I really dont feel like opening each tester to do
this, plus I kind of like keeping vintage gear original.

I have some probes with the MIC connectors, but there are times I'd like
to use a probe with a BNC on my vintage testers.

My idea is to simply make a few adaptors. I have several of the old MIC
connectors, and I have a bunch of the chassis mount BNC connectors
(which I believe is called the "female"). But I am not seeing any
INLINE female BNC connectors. If I could find these female INLINE ones,
I'd simply take a 6" piece of coax, and put the MIC connector on one end
and the BNC on the other. Making 2 or 3 of these should suffice.

Has anyone seen any female INLINE BNC connectors to buy?
Or, is there another method to accomplish this?

Yes, I could solder on the chassis type BNC connectors, but they would
lack shielding at the connector.