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-spindle coolant (requires at least 300 psi)
  • 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 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

Reducing Production Costs for Machining Inconel Gear Housings

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A precision manufacturer focused on the aerospace Industry was using a competitor’s back spotfacing tool for a gear housing, as the Heule BSF had not been introduced at the time his project began. Due to his lack of success with the competitor’s tool (tool breakage as well as insert longevity) the customer was willing to test the HEULE BSF not long after its introduction.

Application Details

Main bore: Ø.278” 
Spotface diameter: Ø.535” Plus/Minus .008
Material: Inco718 
Machine: Cat 40 VMC Mori Seiki: 1000Psi through-spindle

back spotfacing tool


HEULE recommended the BSF-A-0700/040-7.5 using carbide TiAlN-coated blade BSF-M-A-1A-6.0 to obtain a .531 back spotface.

Machining parameters:
Speed: 55 SFM / 395 RPM 
Feed: F=.0006” per revolution / .25 IPM
Coolant: Internal coolant

spotfacing on an Inconel gear housing


The HEULE BSF was able to complete 1 part per blade (10 holes) while the competitor’s tool used 5 blades per part. In-cut cycle time (time to index inserts on competitor not included) went from 62 minutes to 7 minutes 45 seconds. Estimated savings $130,000 amortized over 300 parts per year.

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.