nematOde,
I would think you would like to leave about .002 - .003 for a finish bore and hire someone with an ID grinder to grind the hole to size. Pretty tight tolerance. You could bore them with a boring head but you would definitely have to use a cabide insert and even then the rockwell 60 is going to be very hard to cut. Grinding is your best and most accurate bet. I don't think I would cut them to size before heat treat.
Ken |