Hi Rich, long ago, actually since the start of my machining efforts, I've always been either under machined (too small!), or broke! Which in machinist terms is the same thing! ....So, I have had to invent almost all my own tooling, fixtures, collets and such. It not only had to be simple, but inexpensive, and flexible..... So, early on I started making my own one-shot collets by turning a round disc on my lathe, indexed to my three jaw chuck, with the correct size hole and a slot to provide clamping / spring tension, and bored to the final dia. with a boring tool or drill / reamer.. As long as I always mounted it indexed the same, it was repeatable zero and concentric! I found I could reposition the work by sliding it thru or re-indexing it to my home grown collet and maintain concentricity, as long as the index marks were aligned. So, with the mag bottoms I simply insert the knob thru the homemade collet from the back side, and it is both held tight and true... then I just plunge with a ball end mill ...
... If the stock moves, I simply wedge a piece of aluminum stock between the backside of the work and the face of the 3 jaw chuck.... (really shade tree!!!!
) If I even remotely ever knew what I was doing, I would have probably quit years and years ago!.....
... Best to all, til...lat'r....GT.....
