Erik,

Here’s a response from one of my correspondents:

“ I think it is 7/64” -50, that was a size used back in the day. I looked and I
have a .109”-50, it is #12 gauge Stubs IRON WIRE GAUGE, a bizarre set of sizes
that were used for bicycle spokes a[bout] 120 years ago. “

Before that, he’d suggested:
“...since these are for lock screws couldn’t he just use an adjustable jam die?
Or even a little giant type? I have often fudged a little with those.”

John Ruth
Reminded of his “non-buyer’s remorse” for passing up a very Antique jam die tool
at the Avenel Flea back in its heyday. I put it down because of the price. As I
changed my mind, the guy right behind me bought it!!!