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BSF: Precision Back Spotfacing

Swiss Precision Since 1961


BSF: Large Ratio Back Spotfacing Tool


The BSF tool is a standout in precision engineering, particularly revered in the aerospace and automotive sectors for its single-operation back spotfacing and counterboring capabilities. This tool is engineered to eliminate the need to rotate the workpiece, streamlining production and enhancing efficiency.


Key Features:


Efficient Operation: Operates without the need to rotate the workpiece, utilizing a smoothly swinging blade that activates by spindle rotation and retracts through internal coolant or air pressure.


High Performance: Counterbores up to 2.3 times the diameter of the drill bit, featuring replaceable carbide-coated blades that extend tool life.


Versatile Design: Available in three versions to suit various machining setups:

  • Air: Utilizes air pressure for blade activation and retraction (80 psi minimum).
  • Coolant: Uses through-spindle coolant for optimal blade movement and chip removal (280 psi minimum).
  • Manual: Offers a manual alternative for setups without specialized coolant or air systems.


Designed for CNC Machines: Compatible with CNC machines that support through-spindle coolant, requiring a minimum of 300 psi for optimal performance.


Advanced Mechanics: Functions without an anti-rotation device, spindle direction change, or machine modifications, thanks to a simple swing mechanism enhanced by internal coolant pressure.


Optimal Cutting and Chip Removal: Special coolant pipes and chip-guiding geometries ensure continuous flushing of the blade window and the blade, promoting superior chip removal and consistent cutting performance.


Versatility: Works effectively in both vertical and horizontal orientations.


Ease of Maintenance: All components, including blades, are easily replaceable, ensuring minimal downtime.


Availability: Ready for immediate delivery, available in sizes ranging from 6.5 mm to 20.5 mm (0.256" to 0.807").

How Does the BSF Large Ratio Back Spotfacing Tool Operate?


Crafted with precision for CNC machining, the BSF operates by harnessing centrifugal force upon spindle activation to expand its blade. Controlled by coolant pressure, a piston orchestrates the blade's smooth retraction into its housing. This distinctive design is finely tuned to deliver unmatched cutting precision, unwavering reliability, and seamless chip removal, setting new standards in machining excellence.


View more catalogs/videos and technical information for BSF


BSF back spotfacing tool catalog

How Do I Order a BSF?


View Interactive 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

BSF Case Study


Reducing Production Costs for Machining Inconel Gear Housings


View PDF

"By using the BSF tool we've gone from using 5 blades per part to only 1 blade. Our cycle time went from 62 minutes to 7 minutes and 45 seconds. And we're also estimating over $130,000 in savings." 

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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