CBN Grooving Inserts
Machining seal grooves or retaining ring slots in hardened steel shafts used to require slow, expensive grinding operations. Standard carbide tools simply wear out too fast or chip instantly.
Sundi CBN Grooving Inserts change the game. Engineered with extreme “Red Hardness,” our CBN grades maintain their cutting edge integrity even when groove turning materials above HRC 50. Experience the speed of turning with the precision of grinding—significantly reducing your cost per part.
Versatile Hard Grooving Solutions
Sundi offers CBN grooving solutions for various difficult-to-machine features.
External Grooving: Rigid inserts for machining circlip slots and oil grooves in hardened shafts.
Internal Grooving: Solutions for cutting internal relief grooves in hardened bearing races.
Face Grooving: Specialized geometry for cutting seal grooves on the face of hardened gears.
Profile Grooving: Custom ground forms for V-belt pulleys and specific thread-relief shapes.
Ideal Materials for CBN Grooving
Sundi CBN Grooving Inserts are strictly for Ferrous materials that generate high heat.
Hardened Gears: Machining snap-ring grooves in carburized gear shafts (HRC 58-62).
Bearing Races: Cutting oil grooves or dust seal tracks in bearing steel (52100).
CV Joints: Grooving hardened automotive drive components.
Cast Iron Pulleys: High-speed grooving of V-belt profiles in Grey Cast Iron.
- High wear resistance
- Reduce the machine time
- Stable Performance
- Easy to use
Why Choose Sundi CBN for Grooving?
Grooving hardened materials generates intense heat concentrated in a small area. Sundi CBN is chemically inert to ferrous materials and thrives in these high-temperature zones.
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1. Consistent Groove Widths
In mass production of snap-ring grooves, maintaining the groove width tolerance is critical. Carbide edges wear down rapidly, causing the slot to become narrow. Sundi CBN resists abrasive wear, holding the correct groove width for hundreds of parts without adjustment.
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2. Replace Grinding Operations
Traditionally, parts were heat-treated then ground. With Sundi CBN, you can machine the groove after heat treatment (Hard Turning). This eliminates the logistical bottleneck of moving parts to a grinding machine, streamlining your production line.
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3. Excellent Surface Finish
Our CBN inserts utilize precision-ground edges that produce a burr-free, mirror-like finish on the groove walls and bottom. This is essential for O-ring sealing surfaces where any scratch could cause a leak.

Optimize Your Hard Part Production
Don't let grooving be the bottleneck in your hard turning process. Switch to Sundi CBN Grooving Inserts for precision, speed, and durability.
FAQ
Most frequent questions and answers
A: It is not recommended. CBN works best when generating heat to soften the material in the shear zone. On soft, gummy steels (under HRC 45), CBN tends to have poor tool life due to chemical wear and built-up edge. For soft steel, use Cermet or Carbide.
A: CBN Grooving is much faster. A grinding wheel requires dressing and slow feed rates. A Sundi CBN insert can cut the full groove depth in seconds. While grinding offers slightly better cylindricity for ultra-precision parts, CBN meets the requirements for most automotive and industrial seal grooves at a fraction of the cost.
A: It depends on the cut. For continuous grooving, dry machining is preferred to avoid thermal shock. However, for deep grooving where chip evacuation is a problem, high-pressure coolant can be used, provided it is applied continuously and directly to the cut zone.
