What is the drilling machine hole
The drilling machine hole, that is, need to drill the center of the location, the first pre-hit a small hole (or groove), is the drill head can drill down along the hole to ensure that the drill force around the force to reduce the deviation
The head of the drill bit is sharp, in the actual drilling process, because the drill bit has just begun to be affected by the workpiece force is very large, prone to offset, resulting in drilling hole error is large, less than the design requirements tolerance range requirements.
prone to offset, resulting in drilling hole error is large, less than the design requirements tolerance range requirements
