Rotabroach bits

I have tried different speeds but could never solve this problem until I tried a rotobroach. A rotobroach is like a plunging end mill with a spring loaded center punch to keep the tool centered. It cuts a perfectly round hole quickly and can be used with a drill press or a hand drill. A key to using this tool is to create a good divot with a center punch (included) to keep the tool aligned and try to keep the tool perpendicular to the surface so that all edges stay somewhat equally engaged in the material you are cutting. That said, it’s not tough to use with a hand drill. Another plus is you can cut large holes (1/2? +) without needing pilot holes. This tool is made for body shops to cut spot welds out of car bodies, but it can be used for so much more. Great tool for fast cutting of holes in steel. The only problem with this and other rotabroach cutters is that once you use the tool the heat and pressure of the operation causes the cutter to get real tight on the arbor. Then you have to use vise grips to release the cutter. Well they crack when you grab them too tightly. The cutters need flats to place a wrench on them for removal from the arbor. The cutter threads on, but there is no wrench spots on it, just a nut that goes behind it that rubs against it. If you install the cutter hand tight, it seems okay, but make very sure that you slowly add cutting pressure. I guess I had the cutter on a tiny bit loose and when it touched the material it immediately cross threaded the cutter onto the arbor. No amount of force would remove it (I'm talking pipe wrench force) and emailing Blair was no help as they wouldn't warranty it, so now the kit us useless unless I drop another $45 on an arbor.