I've got a boring jig about half finished to mount a stovebolt connecting rod onto the carriage of my lathe and chuck a micrometer-adjustable boring tool in the headstock. I can rough out a reconditioned rod that's deliberately poured smaller than the crankshaft, and finish-scrape it to a perfect fit with the crankshaft, then shim it for the proper oil clearance. Cutting the lube grooves can be a bit tricky, but with a lathe big enough to spin the rod over the ways and a 4-jaw chuck it would be possible to clamp the big end into the chuck at an angle and machine one groove, then flip it over and make the intersecting one. The alternative would be to freehand oil grooves with a carbide V tool in a die grinder.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!