HEULE Precision Tools


GH-S – The adjustable chamfering tool.

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Adjustable chamfering of interrupted bore edges, front and back in One Operation.

The double bladed GH-S tool allows for front and back chamfering of discontinuous bore edges without requiring the work piece to be turned or the spindle to be stopped. GH-S deburrs the bore edges and provides them with a chamfer featuring a high-precision angle. The cutting force can be adjusted on the tool. The GH-S tool is especially characterized by secondary-burr-free machining of bore edges.


  • Front and back or only back chamfering of discontinuous bore edges in One Operation.
  • Double-bladed tool for high-precision chamfering angles and high-grade chamfer surface finishes.
  • The chamfering thickness can be infinitely adjusted directly on the tool from 0.1 to 2mm, depending on the bore dimension.
  • Exchangeable carbide blades with a material-specific coating.
  • No injury of the bore or thread surface during penetration.


The GH-S chamfering system was the first tool developed by HEULE which fulfilled the basic idea of machining both bore edges in an automatic process, in One Operation and without requiring rechucking of the tool. Although, the GH-S chamfering system has essentially been replaced by the SNAP chamfering system, and both chamfering systems have the same range of application, some characteristics continue to make the GH-S chamfering system the first choice. The dual-blade principle and the rigid connection of the two GH-S blades allows chamfering of discontinuous bore edges up to almost 180°. Also bores with cross-bores can be processed without stopping rotation. The GH-S chamfering system is therefore primarily used wherever bore edges are interrupted by grooves, beads, lateral chamfers, etc. The GH-S chamfering system is also a convincing solution if special chamfer surface finish requirements must be satisfied. The two GH-S blades enter synchronously and continuously with increasing cutting force. This generates chamfer surfaces that are equivalent to those produced by precision turning.


Chamfering is carried out from the same side as previous boring. The two GH-S blades can be radially retracted into the blade housing. They are held inside the blade housing by a control system allowing them to deflect. At the same time, the GH-S blades are interconnected through the control system. The control system responds to the progressively increasing cutting force. It depends on the material quality grade and the chamfer size. The cutting force of the two blades can be infinitely adjusted on the tool. If the cutting force exceeds the blade force adjusted, the two blades will automatically and synchronously retract into the blade housing. When the blades are retracted, the GH-S tool passes through the bore with the spindle rotating. The control system reduces the blade force to a minimum. This rules out any damage to the bore surface or a thread. When moving out of the bore, the blades return to their home position and are interlocked. The back bore edge is now chamfered by backward feed.


  1. Control system
  2. Shank
  3. Blade housing
  4. Blade control
  5. Blade

Product range

The GH-S assortment is comprised of four tool series. Within these series, different diameter graduations are available which cover a small bore diameter range. For details on the assortment, please see the catalog.

Tool seriesBoreChamfer size
GH-S 4 – 10
Ø 4 – Ø 10
0.1 – 0.6
GH-S 10 – 22
Ø 10 – Ø 22
0.1 – 1.0
GH-S 18 – 42
Ø 18 – Ø 42
0.1 – 1.5
GH-S 42 – 100
Ø 42 – Ø 100
0.2 – 2.0