Precision Tools

Swiss Precision Since 1961 

"The BSF tool performed so well that I have now cut out the other five axis roughing, saving us three operations in total and 15 minutes in cycle time." 

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How Does It Work?

The BSF is specifically designed for CNC machining and functions without an anti-rotation device, change of spindle direction or contact mechanism. The blade expands using centrifugal force when activating the spindle. The blade retracts by coolant pressure. The coolant pressure moves a piston which is pushing a pin that forces the blade (closed) into the blade housing. The design of the BSF focuses on optimal cutting performance, chip removal and reliability. The tool and the blade have special coolant pipes and chip-guiding geometries that continuously flush the blade window and the blade itself with coolant. This keeps the whole section clean and allows for optimal chip removal.

View more catalogs/videos and technical information for BSF

Picture of the BSF tool for back spotfacing and back counterboring in metal


The Large Ratio Spotfacing Solution

  • Counterbores up to 2.3xd
  • Replaceable carbide coated blades for extended tool life
  • Suitable for CNC machines with through coolant
  • It works without an anti-rotation device, change of turning direction or any machine adaptations
  • The simple swing mechanism combined with the internal coolant pressure system gives optimal cutting performance resulting in consistent spotfaces and fewer scrapped parts 
  • All tool components and blades are simple to replace 
  • The tool works both vertically and horizontally 

Available from stock for immediate delivery in sizes
from 6.5 mm to 20.5 mm (0.256" to 0.807") 


BSF back spotfacing tool catalog

How Do I Order a BSF Back Spotfacing Tool?

View BSF Catalog

The tools and blades are sold separately and they each have an OFFSET dimension. When combined they equal the
effective counterbore diameter. For assistance, use our online Tool Selector.

1. Choose the tool closest to the bore diameter.

2. Choose the proper blade for the
required counterbore diameter. 

View Application Data Sheet for BSF

Questions? Contact Your Local Sales Agent

BSF Case Study

An Efficient and Reliable Solution for Back Spotfaces on a Wind Rotor Wheel

Download PDF


A manufacturer of wind rotors was looking for a more efficient and stable solution for the application of back spotfaces to bores.
detailed drawing of a back counterbore produced with a spotface tool

Application Details

  • Main bore: Ø14.0 mm
  • Counterbore diameter: Ø22.0 mm
  • Material: GG40
  • Machining: Horizontally with internal coolant
  • Machine: Gantry Boring and Milling Machine Center
Close up picture of the counterbore and backspotface produced with the spotface tool on a steel wind rotor wheel


HEULE recommended the BSF tool with a working length of 80 mm, together with a TiAlN coated carbide blade type BSF-M-E-1A-5.0.

Machining parameters:

  • Speed: N=500 rev/min
  • Feed: F=20 mm/min
  • Coolant: Internal coolant
back spotfacing, wind rotor wheel, HEULE


By replacing their old tool, which needed pre-adjustments, this customer found more stability and a better process capability. The better stability led to a longer blade life for the tool. The customer is very happy with the solution and noted that their process is more efficient, precise, and safe.