In normal dent removal there is a considerable amount of friction between the ball and the surface being worked upon. That is why many repairmen coat the dent balls with Vaseline...the less friction the better. This is especially true as you start working with the larger balls in order to do baritones, some marching brass, tubas, souses, etc We have taken 4 balls, sized 1, 1-1/2, 2 and 2-1/2 (25.4, 38.1, 50.8, 63.5mm) and fit them with roller bearings. There are two high quality bearings for each ball. Then we adapted them so they would screw onto the end of a standard dent rod. The largest three have 1/2-13 threads and the smallest has 3/8-16 thread. These roller balls will roll, rather than slide, as you work the dent out. With little or no friction between the ball and the brass, you will be able to do more delicate work, and do it with less effort. The tool works great on back bows, straight and curved tubing.
