Miniature precision machine with aluminum die-cast head. Quiet, precise and efficient! Grinder with 34 industrial quality bits & cutters with shanks Ø 3/32'' (2.3 mm). High concentricity (maximum run out .001''). This high-revving motor has full-wave electronic speed control capable of producing continuously variable speeds between 5,000 and 20,000 rpm and is usable for extended periods at a time. The ground steel spindle runs in a ball bearing assembly, minimizing play. Six high concentricity collets sized 1/32'', 1/16'', 5/64'', 3/32'', 7/64'' and 1/8'' (1.0, 1.5, 2.0, 2.4, 3.0 and 3.2 mm) along with a collet nut are included. MICROMOT steel collets are hardened and thus have a high, consistent flexibility. They also maintain prolonged accuracy, even after regular use. The triple-slit collet is substantially more difficult to manufacture than the four-slit type, but offers a better load-bearing surface. This is especially important for cutters with small shank diameters. These collets should not be compared with unhardened, four-slit collets of brass and aluminum.