SOLO – The automatic front and back counterboring tool.

Independent spot facing and counterboring, front and back in One Operation.

The SOLO tool allows for production of front and back counterbores and back spotfacing of through-holes with positive control in One Operation without requiring the work piece to be turned. The blade is extended and retracted radially through the action of centrifugal force. The SOLO tool is distinguished by its ease of use and its high production reliability.


  • Automatic front and back or only back spotfacing and counterboring without requiring the work piece to be turned (from the same side as original boring was carried out). 
  • Excellent process reliability and performance due to optimal specification to suit customers' particular applications. 
  • Extremely rugged tool system that is capable of machining soft to hard-to-machine materials, even with highly discontinuous cuts. 
  • Manually exchangeable carbide blades with material-specific cutting geometries and coatings.
  • Can be immediately used on any controlled machine without requiring any torque bracket or other machine connection.


Counterboring is carried out from the same side as previous drilled. A control unit that is sealed to keep out contaminants and coolant incorporates two centrifugal weights. When the spindle is stopped, the centrifugal weights are located in the center. When the spindle is started for the activation RPM, the centrifugal weights move outwards until they meet a stop. When the spindle stops, return springs draw the centrifugal weights back to their home position. A gearing transforms this radial motion into a rotary motion and transmits it to the blade control. An eccentrically positioned bolt in the blade control engages in a groove on the blade. As soon as the blade control rotates, the blade held by the blade housing so that it can be moved is radially retracted or extended. Retraction and extension of the blade at the activation RPM or spindle stop are abrupt and without delay. The fixed positions of the retracted and extended blades are pre-defined and cannot be modified by any force acting on the blade from the outside. The blade can only be moved out of the two fixed positions by activation RPM or spindle stop.


  1. Tool head 
  2. Shank 
  3. Blade housing 
  4. Blade control 
  5. Blade

Product Range

The SOLO tool head is available in stock in two versions. The SOLO for machining materials with high cutting speeds. The SOLO2 for machining materials with low cutting speeds.

The blade housing, blade control and blades are specified to suit each particular application.

Position of blade spindle stop Retracted Extended
Retract speed Spindle stop 1900 rpm
Extend speed 1900 rpm Spindle stop
Machining speed > 1900 rpm 0 – 1500 rpm

SOLO Product documentation

60 Years Heule