There are one or two cutters, two milling helical grooves, conical right at the top of the cutter and cutting fluids and chip in and out of the channel. This bit is typically used to open holes in the workpiece, or expand the existing hole. When fast rotating axially into the workpiece and drill with a little pressure, while the key is not to rotate. Sometimes carrying out drilling work on the lathe, drill fixed key rotation, automatic car more drilling, drill and workpiece rotation in the opposite direction, makes productivity more increased.
All cutting tools, such as cutting force compared with section size, then the cutting stress per unit area to drill for maximum, spiral cutting slot it virtually the entire plant in the common application is a rotation of the cutting tool at the top of the twist drill, to drill or to expand an existing hole. Its upper body half removed; but due to support by external critical holes so bit should generally not fracture.