taper

The half-angle = arctan(0.5*(0.75 - 0.63) / 1.0) = 3.43 deg. However, I suspect your measurements may not be accurate. Common tapers for tie rods are 1.2"/foot or 1.5"/foot. Your measurements give 1.44"/foot. If your bottom diameter were actually .625" that would be a 1.5"/ft taper or 3.58 deg. half angle.

You are right, I checked my measurements again a bit closer to the bottom edge and also looked at the manufacturers specs, which were

Thank you for your assistance, I have to try to re-learn trig for my metalworking, as I did not use it at work. I have no problem with algebra as it was used in calculating formulae and proportions of ingredients for quality control, which was my job. I would probably take a couple of days to get up to speed with calculations as I retired just over 15 years ago and, of course, my employer had to put on 2 people to do my job and they were still slower than I was.

Thanks,

Alan

Put the tie rod end in the lathe and set the compound parallel to the taper with an indicator.

jsw