These boring bits are designed for accurate boring and the two wing cutters and two spur cutters prevent bottom side tear out. All 6" long bits come in a wooden case and the 57mm long bits have a 10mm x 20mm shank with an adjustable top screw making them compatible with most boring machines. The 3557E is designed with a 3/8" shaft to fit in most drill presses.
Drills all composition materials, solid surface materials, plywoods, hardwoods, and softwoods. Use on automatic and manual multi-spindle boring machines.