Both the centre hole and the oil hole are drilled in the soft stage and the hole quality requirements are usually high.
As the centre hole is deep in relation to the hole diameter, chip evacuation is always a challenge. The solid carbide gun drill
CoroDrill 428 generates close tolerances (IT8) and is ideal for large batch size production, thanks to the high process security and high metal removal rate.
CoroDrill 460 is a versatile micro-grained solid carbide drill with a welcome combination of hardness and toughness, high wear resistance and long tool life. High cutting data possibilities and excellent hole quality with minimum burr are some of the benefits.
The consistent tool life also leads to improved machine utilization, less tool changes and high security in unmanned mass production. The drill can be reground up to three times, extending tool life even further.