Precise and efficient drilling
in one single step

Pilot drilling and drilling

Because of its special drill tip geometry, CrazyDrill Cool SST-Inox, the drill with through-tool coolant, has a high degree of self-centering capability and can therefore be used on regular and straight surfaces for drilling depths up to 6 x d without a centering or pilot hole.

Higher requirements: for irregular, rough or inclined surfaces or for the highest degree of position accuracy and for drilling depths up to 40 x d:

CrazyDrill Cool SST-Inox and the pilot drill CrazyDrill Coolpilot are the perfect combination. Pilot drilling with CrazyDrill Coolpilot or CrazyDrill Crosspilot (on inclined surfaces) is the perfect starting point for accurate drilling (position and alignment accuracy). The pilot drill is a guarantee for position accuracy due to its short and sturdy design. Moreover, the follow-up drill (CrazyDrill Cool SST-Inox) is guided cylindrically by the pilot hole, thus guaranteeing perpendicularity and alignment accuracy (straightness).

Predetermined tool tolerance guarantees the hole quality as well as a stable machining process (no jamming).

Tolerance of pilot drill CrazyDrill Coolpilot (m5):
≤ 3 mm (.118”): + 0.002 mm /+ 0.006 mm (+.00008” /+ .00024”)
≤ 6.35 mm (.250”): + 0.004 mm /+ 0.009 mm (+.00016” /+ .0004”) 

Tolerance of pilot drill CrazyDrill Crosspilot (drilling on inclined surfaces) (k6):
≤ 3 mm (.118”): + 0 mm /+ 0.006 mm (+ 0” /+ .00024”)
≤ 6.35 mm (.250”): + 0.001 mm /+ 0.009 mm (+ .00004” /+ .0004”) 

Tolerance of follow-up drill CrazyDrill Cool SST-Inox (k5):
≤ 3 mm (.118”): + 0 mm /+ 0.004 mm (+ 0” /+ .00016”)
≤ 6.35 mm (.250”): + 0.001 mm /+ 0.006 mm (+ .00004” /+ .00024”)

Drilling process

General information

In the industry of metal work tools, shorter processing times are always in high demand. At the same time, the requirements to the manufacturing precision and the process reliability are extremely high. In order to fulfill these requirements, the "machine tool – spindle – tool – tool holder" system need to be considered as a whole (see additional info).

For the use of the types of drill bits CrazyDrill Cool SST-Inox and CrazyDrill Coolpilot respectively CrazyDrill Crosspilot, Mikron Tool has defined a fast and process-reliable procedure which achieves optimum  drilling results.

Drilling up to 20 x d (for 6 x d recommended on irregular, rough or inclined surfaces or for highest degree of position accuracy):

  1. Pilot drilling in one step
  2. Drilling in one step

Pilot drilling

  • Turn on internal cooling
  • Drill with CrazyDrill Coolpilot (irregular or rough surfaces) up to 3 x d with simultaneous chamfer of 90°
  • With CrazyDrill Crosspilot for all versions on inclined surfaces up to 2 x d





  • Turn on internal cooling
  • Drill with CrazyDrill Cool SST-Inox in one step with recommended drilling speed and feed (see cutting data chart)






After the drill reached desired cutting depth, return at increased feed rate (or in case of perfect conditions rapid traverse) to safety position. With CrazyDrill Cool SST-Inox it’s possible immediately to get into the material and drill, using the recommend cutting speed and feed.

Drilling up to 30 x d and 40 x d:

  • Pilot drilling in one step
  • Drilling in one step

 Pilot drilling





  • Turn on coolant. Enter the hole at a maximum speed n = 500 rpm and vf = 1’000 mm/min, up to drilling depth 2.8 x d (drill should not touch the bottom of pilot hole).
  • Increase speed as per cutting data chart and wait until the desired drilling speed is reached. Program well in case of slow spindle acceleration.
  • Drill in one step up to 30 / 40 x d with recommended cutting speed and feed rate.





Exit from bore

  • After the desired drilling depth is reached, return with the drill to drilling depth 3 x d at feed rate or reduced rapid traverse.
  • Reduce speed to n = 500 rpm.
  • Exit the bore at speed n = 500 rpm and vf = 1‘000 mm/min.




Tested and approved

Mikron Tool has determined the ideal cutting parameters (drilling speed to tool life ratio and process reliability) when using CrazyDrill Cool SST-Inox. These are listed in the cutting data tables according to drill diameter, drilling depth and material to be machined. The detailed cutting data tested by Mikron Tool, such as cutting speed vc, feed rate f and drilling impact Q, permit a quick and secure machining.

The overview of the cutting values table according to material group, material type, hardness degree and tensile strength, material number, DIN and AISI/ASTM/UNS permits quick determination of the parameters to be used.


An impact-resistant and user-friendly drill packaging is absolutely necessary for CrazyDrill Cool SST-Inox. Mikron Tool offers all tools of the CrazyDrill Cool SST-Inox family in a high quality, single package.

Notes or further questions

Please find more information about tool holders, cooling or lubrication under “Additional Info”.

Mikron Tool has an international team of cutting technology experts who are pleased to answer your questions (how to use a drill, tools, machines, tool holders, cooling, machining process…).

Use this link to contact us directly.