Annular Cutter Arbor From R8 3/4" End Mill Holder

[Radioman]

I’ve also done this in my small machine shop. I inherited about 50 annular cutters from my late father who was an ironworker. Did you try to drill your hole with a carbide end mill? I would figure a carbide would’ve gone right through that three-quarter holder like butter? My end mill holders don’t seem to be that hard that they wouldn’t yield to a carbide end mill. My Bridgeport is a 1 hp three-phase that I’m running on a solid-state inverter so I’m only getting about 2/3 of a horsepower out of it. Any annular cutter bigger than 1 inch I have to be real careful with or I’ll stall my motor. Someday I’ll update to a 2 hp single phase. Maybe before I diet not.