Trepanning is used for larger hole diameters and where machine power is limited, because it is not as powerconsuming as solid drilling. The trepanning tool does not machine the whole diameter, only a ring at the periphery.
Instead of removing all the material in the form of chips, a core is left in the centre of the hole – consequently, this method is for through-hole applications.

Use T-Max® U Trepanner R416.7 for trepanning.

T-Max® U
Drill diameter
mm (inch)
Drill depth 2.5 x DC
Hole tolerance ±0.2
Surface finish Ra 2–7 µm



The drill is designed for drilling solid workpieces as well as stacked components, with or without air gaps.

Set-up recommendations

Adjusting screw
Rotating and non-rotating drills

The peripheral insert must be set 0.20 mm (0.008 inch) behind the inner cartridge.

Non-rotating drill
  • The drill should be positioned with the inserts on the horizontal axis.
  • The drill must not be offset from the workpiece centerline, with reference to the peripheral insert, by more than -0.15 mm (0.006 inch).
  • The peripheral cutting edge (P) should be set to within +0.1 mm (0.004 inch) in the horizontal plane from the centre-line of spindle (CL).


Core handling

Vertical set up

The core will fall down when drill breaks through, which does not normally cause a problem.

Horizontal set-up

Long and heavy cores may require a core support to prevent the core from falling down and chipping the inner insert.

Rotating drill - core fixing
Drill a hole into the core. Fix plug in the hole to prevent the core (C) from falling.

Non-rotating drill - core support
If the drill is fitted with a core support, the drill should be mounted with the
cartridges located on the vertical axis and the peripheral insert downwards.


Cutting data

 ISO​ Cutting speed
vc m/min​
 Steel​ 100-250​  0.07-0.20
 Stainless steel​ 100-250​  0.07-0.20​
 Cast iron​ 100-250​  0.15-0.25​
 Aluminium​ 250-400​  0.12-0.22​
 Titanium​ 40-100​  0.08-0.16


Graphs for T-Max® U trepanning tools – R416.7

Net power Trepanning torque
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