This is the second AC35 my company has bought. The first is about 2 years old and still going strong I hope it is the same quality as our other one We have used them to drill 1 1/16" diameter holes in 1 1/4" mild steel to a 1/2 1/4" hole in 1/4" thick steel plate. Both paid for themselves right away in terms of the time it took to drill holes compared to the regular 1/2" drill bits we own.