Extractor rods get bent due to abuse. The main culprits are dumbf**ks that flip the cylinder closed or the dummys that beat a cylinder open when the rod has backed out on the threads. I personally would not waste my time trying to true a bent rod. I'd get a new one. The center pin may be okay. You can check it by simply chucking it up in a hand drill. If it spins with a wobble, buy a new one. Simply replacing these parts may not bring things up to snuff, especially if your cylinder had been hammered open. There is an excellent chance that the cylinder yoke is also bent. You check this with a special cylinder yoke alignment tool(available from Brownells). You can do a less exacting check with a feeler gauge. Insert the largest thickness gauge into the barrel cylinder gap that will fit. Start pulling the trigger and get that cylinder moving with the feeler gauge in place. If you feel a spot where there is some resistance or drag, as the next chamber rotates up, most likely you have a bent cylinder yoke. The Kuhnhausen shop manual explains how to correct this. I cannot stress enough how important it is to revolver accuracy that the cylinder is square to the barrel face............keep us posted........you are now a gunsmith in training........if you so wish.