Designed to endure
demanding environments


Doofor high frequency rock drill equipped with a hydraulic back hammer
High-performance hydraulic rock drill

Doofor DF550L-EXT is a high-frequency rock drill equipped with a hydraulic back hammer. The back hammer enables removing stuck drill steels from the rock and opening the threads of lines of drill bars in extension bar drilling.

The DF550L-EXT has a very low overhead, only 84mm from the drill center line. The rotation motor of the DF550L-EXT can be installed on the right hand or the left-hand side.

The rock drill has a separated flushing box. Flushing media can be water or air.

A flushing head can be turned upside down. The motor can be on the left or right. Motor fitting direction can be specified (up, down or side). Accumulator valve direction can be specified.

Optimal maximum hole diameter for the DF550L-EXT is 76 mm.

The rock drill can be equipped with male R32, R38, T38 or T45 shank adapter (striker bar).

Technical Data
Nominal power class17 kW
Percussion pressure160 bar
(Percussion oil-flow)(95-120 litres/min)
Rotation motor*125 cm3
Speed max.250 rpm
Torque*796 Nm
Oil flow*40 litres/min (max. 90 litres/min)
Gear ratio65/40
LubricationAir-oil mist, min. 200 g/h
Flushing air pressure5–7 bar
Flushing air flow4000 litres/min
Flushing water flow150 litres/min
Weight170 kg

76 mm

Optimal maximum
hole diameter

17 kW

Power class

R32, R38
T38, T45

Shank size



*) Numbers given are for standard rotation motor (125 cm³) at an intermittent pressure of 275 bar [3989psi]. Motor options are 80 cm³, 100 cm³, 125 cm³, 160 cm³, 200 cm³, 250 cm³ (200 & 250 cm³ motors can be installed on the right hand side only). For professional use only as a component of a hydraulic system.

Feed force (pressure) must be adjustable during operation. Rotation torque and oil flow values given are for a typical rotation motor. See full brochure for detailed information on different rotation motors. Percussion pressure mentioned is a recommended value for a typical application. The product is intended for professional use by skilled personnel. Doofor reserves all rights for changes without prior notice.

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