Keeping a tap straight and square the the hole you’re tapping is really important. Not only does it ensure that the threads are strong, it helps prevent you from breaking off the tap in the workpiece. But it’s not easy: holding it perfectly square to the work while you turn it takes a lot of practice. Or a better tap wrench…

In use on the lathe

I use a Wilton piloted tap wrench whenever possible. It’s pretty much like a normal tap wrench except that it rides on a 1/4″ diameter shaft (the pilot). The shaft is held in a drill chuck, and the wrench is free to spin on the shaft and slide up and down it. This lets the tap advance as the threads are cut. It works on the lathe, the mill, or the drill press.