Roll taps, or form taps, unlike conventional cutting taps, form threads through material deformation, rather than by cutting the material. As a result, no chips are produced in the process. Since there are no chips to interfere with the tapping process, roll taps produce stronger, cleaner threads, with excellent surface finish. And since there are no chips to clog flutes or collect in blind holes, there’s less chance of tap breakage.
Roll taps require a larger drill than a cutting tap of the same size, to allow room for the material to flow when creating the threads. The grain flow of the material follows the contour of the formed thread, creating a stronger thread, especially in materials that work harden, like steel and stainless. Generally, roll taps can be run at higher speeds and feeds than cutting taps, and have a significantly longer tool life. They are well suited for smaller holes and materials that require a stronger tap.