Port holes

The large diameter must be created in a drilling operation. Must be machined without vibration to obtain narrow diameter tolerances and perfect surface roughness.



The step drill in pre-form carbide with special internal coolant and center point makes it possible to increase cutting speed.


  • Reduced machining time
  • No vibration
  • Safe process
  • Excellent surface quality
  • Long tool life


Machining process


Step 1: SC step drill


Step 1: Solid carbide step drill

Drawing no. 212891/999997, N = 1675 rpm, Fn = 0.4 mm/rev.


Step 2A: UM tap


Step 2A: UM tap

Drawing no. EH1480.554


Step 2B: UM thread mill


Step 2B: UM thread mill

Drawing no. 256938.12x014