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Front and back chamfering of interrupted bores – even with large burrs – in one single pass

  • Processing of demanding materials with large burr formation, without producing a secondary burr
  • Dimensionally stable chamfer with high-quality chamfer surface
  • Chamfering capacity continuously adjustable, depending on the bore dimension from 0.1 to 2.0 mm
  • Standard range for bore diameter 4.0 mm – 23.9 mm
DEFA | Catalogue
pdf ・ 2,0 MB
Tool Selector


The DEFA range consists of three tool series, each covering a certain bore diameter range. The chamfering capacity is variable and infinitely adjustable directly on the tool, ranging from 0.1 to 2.0 mm, depending on the bore diameter.

BoreChamfering capacityTool series
4.0 – 6.6 mm 0.1 – 0.6 mmDEFA 4-6
6.0 – 10.1 mm 0.1 – 0.85 mmDEFA 6 – 10
9.0 – 23.9 mm 0.1 – 2.0 mmDEFA 9 – 24

Should no standard tool solution be available for your application, HEULE can make a detailed application analysis. The result will be an application-specific solution. 


The DEFA chamfering tool is characterised by two interchangeable carbide blades with a unique cutting edge geometry. The two chamfering blades are activated by a spring-loaded blade control. This pressure and the resulting blade force can be adjusted according to the workpiece material.


The rigid connection between the two chamfering blades allows the processing of bores with longitudinal grooves or crossbores. By turning the adjusting screw, the chamfer diameter can be adjusted.

Tool Concept
  1. Blade
  2. Blade housing
  3. Blade control
  4. Spring
  5. Fixing screw
  6. Clamping piece
  7. Tool body
  8. Clamping screw
  9. Eccentric
  10. Adjustment screw
  11. Clamping screw
  12. Shaft


Arbeitsweise Faswerkzeug DEFA

Process steps description

DEFA removes the burr from the front and back bore edges and produces chamfers of the correct diameter without rotating the workpiece or stopping the spindle. First, the blades remove the burr on the front edge of the bore. An inclined, non-cutting control surface on the blades controls the cutting of the chamfer and the retraction of the blades into the tool body as soon as both blades touch the workpiece surface.


The DEFA tool can then pass through the bore in rapid feed. Due to the blade’s crowned surface, the DEFA can pass through the workpiece without causing damage to the surface of the bore. When exiting the bore on the back side, the blades return to their neutral position. In working feed, the back edge of the bore is deburred and chamfered.


Visit our downloads section for detailed information, videos and operating instructions. 

Application examples
Chamfering tool in operation
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Aircraft Component | Reduced production time thanks to the elimination of the manual deburring process.
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Steering knuckle | Increased economy thanks to the HEULE chamfering solution.
Would you like to discuss your chamfering requirements?

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