Today I finished making the parts I'll need to rebuild the 310. The bolt needed a handle, a cocking pin and something to replace the locking ball.
I suspect the missing original handle has broken off, it had smallish 6-32 threads and I guess was made from mild steel. I made the new one in chrome-moly steel, with 8-32 threads - of course the bolt is re-drilled and threaded accordingly. The cocking pin is made from O1 tool steel. I made a mini plunger to replace the missing ball (funny: about the same size as a 13xx/22xx safety ball
), using a broken drill bit. I chucked it in my hand held drill and ground it using my dremel with a cut-off disk.
The pump arm also had a hidden issue, a very worn link rivet, with the corresponding hole in the link elongated, and a bent, worn and cracked spring. I made a new rivet out of O1 again. The elongated hole was slightly enlarged and rounded, and a piece of 4140 steel was ''riveted' in place, then ground flush and re-drilled to the correct size (3/16''). The spring wasn't salvageable, so I made a new 5-leaves ''spring pack'' out of an old chainsaw rewind starter spring.