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Swiss Precision Since 1961

The Adjustable Chamfering Tool


The Adjustable Chamfering Tool

  • Controlled chamfers over a range of adjustments
  • Chamfering thickness can be infinitely adjusted directly on the tool, depending on the bore dimension
  • No reversing the spindle or indexing the work piece saves cycle time
  • Front and back or only back chamfering of bores in hard-to-machine or highly burr-forming materials 
  • Ideal for Inconel and other exotic materials
  • Dual cutting system for machining bores with longitudinal grooves, cross-bores and open bores with discontinuous cut
  • Exchangeable carbide blade with material-specific coating 
  • Blade geometry has a sliding surface that allows cutting chamfers without damage to the bore surface or of the thread during penetration
  • Widely used by the world's leading aerospace manufacturers


In Stock & Available in sizes from 4 mm to 36.2 mm (0.157" to 1.425")


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How Does It Work?

The DEFA tool cuts a pre-adjusted chamfer diameter. The blade force keeps the DEFA blades out to the predetermined setting, thereby defining the chamfer diameter. The blade’s upper and lower cutting edge permit machining in both forward and reverse directions. As the DEFA blades enter the material, the force occurring through the feed on to the chamfer definition surface causes the blades to retract radially along the axis of the chamfered surface. The cutting width is constantly reduced. The definition surface angle determines the chamfer angle. Damage to the hole or thread surface is prevented by the sliding surface geometry of the DEFA blades.


View more catalogs/videos and technical information for DEFA


DEFA chamfering tool catalog

How Do I Order DEFA?


View DEFA Catalog


1.To select the correct tool you must know the hole size and chamfer size required. Cutting blade options also include front & back cutting and back only cutting.

2. Use the minimum hole column in the DEFA catalog to choose the tool holder best matching your drill hole size. Check to make sure the chamfer diameter requirement does not exceed the maximum chamfer.

3. Calculate the ØD2 (over the blade) diameter (ØD2 = ØD + .080”) and add this dimension as a suffix to the order number. 

4. Add “p” to the order number if you need the tool with an End Plug. Leave blank for tool with straight shank.


View Application Data Sheet for DEFA


For more assistance, see our online Tool Selector.


Questions? Contact Your Local Sales Agent

DEFA Case Study

 Replacing Manual Deburring of Inconel in the Machining of Aircraft Components

View PDF

Need help selecting a tool? Visit our online Tool Selector and go to the Locate Agent page on our website to find your local technical sales representative. For more assistance, contact us at or 513-860-9900 and we'll be happy to point you in the right direction.  

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