Thirty to forty some odd years ago when I was doing some basic gunsmithing it became obvious that I could not afford the number of 6-48 taps that I was going through. Someone had posted pictures of this unit that looked to me as it would be of great benefit to me, and that proved to be so. I have not broken a 6-48 tap since building this unit. I made a couple of alterations to the original, one was adding some bronze bushings and the other was to use a small vise rather than the holding method as presented, which can be used but I have never had a need for anything more than the vise. It is quite heavy and very stable when locked down but I seldom need to do that.