The Sphere Cutting Tool Kit is designed for use with Covington's 16" Flat Laps. The kit will make spheres from 1-1/4" to 4" in size. Cups have a 1"-8RH threaded bore to fit horizontal lap arbors. This kit consists of a special splashguard and one (1) each: 1", 1-3/8", and 2-3/8" cutter cups. Sphere cutting on this unit is simple, just hold the rough sphere with a gloved hand and grind it on the proper size sphere cutter cup.