- Oct 28, 2019
I am hoping to get some advice here on a problem I have been attempting to solve for a while. I need to thread the inside edge of SS hemisphere to screw a brass ring onto. My issue is finding a way to hold the bugger and turn it. In the four jaw it either slips or I risk collapsing the part. In this jig I have a brass washer shaped to fit the inside but two issues being the hole was not made bang on center (I won't even go through my troubles with drilling that thing on center). Still slipped in the jig. I know that I need to turn the inside so that the threading surface is cylindrical which works well enough at speed in the lathe but when it is time to thread it, the tool always grabs hard enough to spin the part in the jig no matter how tight I make that little 32-10 bolt. The only thing I can think of at this point is making a small keyway in the jig. My other thought is to create a large ~60mm tap and try to thread the part like an orange in a juicer. I am hoping y'all might have some better ideas!