Well WE know THAT isn't you. NO SNOW and TEE Shirt weather. But the jamb nuts sure standout.
I doubt it is a stud threaded into the shaft. When you weld the bolt on use a hard 8 grade fine thread black finish bolt..
Double nut the nuts to your bolt, this gives you somethin to clamp the ground to And protect the threads. A bit of No Seize won't hurt just keep it out of your weld.
The manufacturer used a double nut for a reason, I am "thinking" They didn't want the ram drawn up to bottom of wedge plate so tight That it may break off. (Just a thought). Protect the chrome from weld spatter maybe a small piece of pipe and taped at the end. a beverage can or aluminum strip wrapped around the ram a few times with with a radiator hose clamp or 2.
@StumpShot says something like "Remember it was broke when you stared"
GOOD LUCK