FAMAG Replacement Depth Stop Frame Without Bush 1622/1623/1630/1663 Series, 1621100 - Depth stop supported by ball bearing for FAMAG-Forstner bits with exchangeable guide bushings, The depth stop is mounted on the stalk and the drilling depth has to be adjusted. This makes it possible to drill stud holes with exactly the same depth at all times. The bushings are rotatably supported by ball bearings and thus produce no disturbing marks on the workpiece surface. For larger drilling depths, it is possible to mount the guide bushing in reverse form, so that you can reach a larger adjustment of the depth stop. Depth Stop made of resistant ABS plastic, guide bushing made of steel. RPM-see speed of Forstner bit