When I removed the propeller shafts a while back, my main concern was whether or not I would have to replace them. I have not owned the boat since it was new, and I have no idea what kind of stupidity the previous owners engaged in. So, before I invested any time in cleaning and restoring the shafts, I wanted to determine if they were straight. The pics below detail my setup - nothing special, just a couple machinist V-blocks and a dial indicator. The V-blocks were placed at the far ends of the shafts - one next to the taper for the transmission flange, the other on the clean section of shaft that rides in the cutlass bearing. I then placed the dial indicator at various places on the shaft, and gently rotated the shaft to get a reading.