I bought one of these, Sykes Pickavant it did not perform very well at all,,the cutting teeth all sheared off, I suspect it was improperley tempered, never agaiun.I have a proper spotweld bit that I use with cutting paste, a relatively low speed (600 RPM'ish) and plenty of pressure.
depends on how fast they run and if u get the drill parralel to the job. i use hole cutters nearly every day no problem but now and then they cut through on an angle start running off bite in snap a tooth off and take all the the rest with itI bought one of these, Sykes Pickavant it did not perform very well at all,,the cutting teeth all sheared off, I suspect it was improperley tempered, never agaiun.
Digger6135