High precision woodworking, metal mortising machines One year warranty, guide use mortising machine for woodworking

Excerpted from the Internet, for reference only

For drills with a diameter of less than m, Mitsubishi recommends that an initial hole with a depth of 1 to 2 times the diameter be drilled with a rigid center drill first. The tip angle of the pilot drill should be equal to or greater than the micro-drill apex angle of the final drill hole. If the apex angle of the center drill is small, then when the micro-drill is cut in later, the two cutting edges contact the workpiece first, which is likely to cause chipping.
If the pilot drill is not used, this method can be used: the feed rate at the beginning of the micro-drill is much lower than the normal feed rate thereafter. For example, the diameter of the drill bit is 1.61m, the hole depth is 12.7mm, and the normal feed rate is specified as 0.0508mm/r