Really good video! You are the first person to show how it is really two cutters in one. I just bought one of these (Ry-Tool brand - made in Taiwan) and saw immediately that there are two cutters - so I was quite impressed, as it wasn't cheap at A$27.95. I just used it for the first time (never have tried dealing with spot weld sections previously) and found it worked well - however I would recommend that a cutting fluid is used, as well as to keep the drill at a slow speed - to prolong the life of the teeth. I used WD40, although I'm sure there are more efficient ones around.
