... the adjustment function can control the quality .GD-13 drill bit grinderEasy to operate, unskilled workers can learn ... is electronic and powerful, frequency stably, extra motor life.Specifications: Drill size Dia.2 ~ Dia.13mm Point angle90° ~ 145° ... phase AC 110V AC 220V Motor 1/4HP 180W R.P.M. of motor 5,300rpm Diamond grinding ... : Dia.2.5,3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13mm collect holder set hexagon ...