Custom Machining Jigs

I've been fortunate to have a little time this summer to work on a project or two that are less than mission critical, while still being potentially useful...case in point a custom chess set design that I'd like to make available to support our engineering program, and would like student assistants to be able to manufacture for me. I'd finished the lathe programs for all the pieces and only had the slot in the bishop's mitre and the knight's nose to finish and was wondering how to make it simple