Ok, the part in the photo is a Servo Horn for "giant scale" rc aircraft (80" wing span and up). I need to make some "unique" configurations to fit into planes that the stock ones (or even after market ones) just won't fit. So, here's the question: as close as I can measure, the id of the spline hole is ~ .215". I can't measure the depth of the spline for major diameter. There are 25 splines in that little bugger. (edit: material is aluminum) So, how do I make splines that small? ( I have a Sherline lathe & mill available). thanks for reading and any / all suggestions.