"This is another bad revue on these bosch holesaws. at one time you could rely on bosch but they seem to be getting like other companies and the quality is declining. These holesaws are ok for wood and plastic but only good for steel a couple of times then blunt. I use cutting compound and take my time but they are throw away in no time. My main use is on board boats and steel is my norm. even the expensive ones from other companies are not as good as they were."