Face off the end of your drill rod & put in a small center drilled hole, making sure it's smaller than the smallest diameter you'll turn...I use a #2 or #3 Keo C.D. Zero out your indicator on the face, and rough turn the first 1 inch EXACTLY to length. It is as important to be as accurate to length as it is to diameter...in order to precisely reproduce the profile. Rough turn, leaving maybe .015 above your largest dia. in this 1 inch long segment. Then, just start at Z 0. and turn each .100 to it's finish diameter. As mentioned earlier, keep marking polarity on the workpiece with a magic marker so you'll be able to pull STRAIGHT out when the chuck jaws are loosened, to try to maintain good concentricity. Ok!!...10 diameters done...only 160 to go! LOL