The same type of nut was used on handsaws in the 19th century and various other old machinery. Generally known as "Split nuts" Thinking about it, most binder bolts also resemble the type of saw nut that replaced split nuts starting around 1870ish. The usual answer for old tool retrogrouch equivlents is to get a wide blade screwdriver and fie or hack saw a slot for the bolt. Alternatively, spend years digging through old tool boxes at flea markers and tag sales until you find a century old one. I've done both, but the former is much quicker.
Split nut saw nuts:
https://www.amazon.com/Taytools-1157.../dp/B07CJ8SGJV
saw nuts:
https://www.amazon.com/Chicago-Screw...79480386&psc=1