Drill hole surface quality

Typical hole quality characteristics

1. in 42CrMo4V, Ø 14.5 mm




2. in GGG40, Ø 10,0 mm



The overall total of the maximum positive and negative deviations is the sum of the total run-out in relation to the black circle as measured on standard instruments (dRmax). The red lines at the hole centres indicate the direction and amplitude of the displacements AV (Axis Shifting) of the produced hole from the true centre point. The parameter showing the largest deviation is decisive for the IT quality class of the hole in relation to the tool diameter. The black circle in the diagram represents the nominal hole diameter which the tool should ideally produce.
The red circle indicates the form actually produced. The mean value of the radius of the red circle, i.e. the average diameter, is shown by the blue circle. (with our 60.6003 drills the average diameter is practically identical to the actual diameter produced).