I gave 5 stars because this set is a good value for what it can do. But it's important to understand what it can't do if you want to be satisfied. If your aim is to thread soft materials such a brass or 6061-aluminum, etc. then this set is a good value and will serve. If you want to tap mild steel, you can do it as long as you are really patient and diligent with procedure (turn, back off, turn, back off, turn back out, cutting oil, and so forth). If you are interested in higher-carbon steels, heteroalloy steels, or exotics like titanium, this set isn't what you want.Two more things:1) The supplied tap wrench is barely adequate for the smallest taps in the set and you have to be extra careful and patient to avoid stripping, and rounding off, the shanks on those taps.2) The taps are definitely through taps, not plugs. If you want to tap a blind hole, you'll have to drill a little deeper in order to get a full width thread to your intended dept.