I bought it last year and use it a lot. I went through a whole box of 14mm x 140 dominoes which equals about 70 tenons meaning I made at least 140 70mm grooves. The bits are well cut and true to size. It's going to be a bit boring, but I'll sharpen it and make 140 more grooves. In fact, I've made over 140 slots on this drill bit, made trial cuts, and done a few experiments for projects. Most of the cuts were made in pine, but I've also used it in white oak for door projects that required 40 to 50 70mm slots. The beat played well.