This window displays dimensional data for a large number of inch and metric center drills.
One use for a chart like this is to quickly see which center drill is the optimal size for the twist drill that's going to follow it. Center drills are relatively weak, and it's normally beneficial to use the largest size allowed by the finished hole size.
Another use would be to help select the correct center drill size for machining a center in the end of a shaft, in cases where the blueprint wasn't specific.
It can also be helpful in some machining situations to know the pilot length or body diameter of a center drill.
Close Tolerance Software - Tools For Machining Professionals
