Reaming parts: a four-edged outer tooth chip reamer, each cutting edge precision by a main cutting edge and a minor cutting edge components. In operation, the main cutting edge of the cutting play a major role in the wiper from the secondary cutting edge role. Reaming holes completed subsequent to the drilling part of finishing, to ensure the accuracy of the hole (larvae L shape and position accuracy and surface roughness).
Chamfered portion: After finishing the hole is completed, continue to use the chamfering of the hole is chamfered. Chamfer should adopt manual control.