As a last resort you could take a long 3/8-16 bolt, cut off the head, and cut a 3/8-24 thread onto the unthreaded portion of the shank. Then trim off both ends to get the thread lengths you need. I do that on a lathe, but if you're careful with an adjustable die the same thing could be done in a vise.
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!