I've been doing this for several years now on a regular vertical mill equipped with a DRO, and I posted a pic collage on the Fox site as well as here a while back. It is an excellent method. Your holding fixture is similar to mine although I can use a shorter end mill, and mine doesn't use a jack screw that can mar the side of the hook. My fixture sits on parallels in the machine vice same as yours but is longer to help support the weight of the barrels. More info for readers... I don't do it commercially. Frank Silvers

I AM SILVERS, NOT SLIVER = two different members. I'm in the northeast, the other member is in MT.