Stan,
I am not sure of the thread size. I think it is probably metric. I don't have a drill press so I used a hand drill and held the shell on top of a vise. I did get an old style hand roll tool thru Charles that worked with the 20 ga but slips with the 32 ga. You can interchange the heads with it. I did not have a lot of time when I did the few shells with the pics so I will be working with it again soon. I think the drill press will work great because you need pretty good pressure to do the crimp with the plastic shells. I have not tried any paper shells yet. One advantage to the drill or hand press is that in a 2 3/4 or 3" hull you can do a nice crimp. I have found that my 20 ga hand crimper tool has too short a space for the longer hulls. Also by having the hull verticle the top overshot seal will not fall out like it does sometimes in the horizonal position. I have a bunch of new 20 ga active hulls and this is going to work great on them. In hulls that I cut off I like federals the best for roll crimping. The hulls seem be a good material for roll crimping and I have done some a number of times in 12 and 20 ga. I have had good results with fiocchi 16 ga and 28 gauge. Chedite also ok.
