These belts are made of the hardest known materials on earth. They use Diamonds or Cubic Boron Nitride.
DIAMOND:
A diamond grinding belt is
a specialized coated abrasive tool that uses synthetic diamond particles bonded to a flexible backing for precision grinding and polishing
Structure and How It Works
Abrasive Layer: Synthetic diamond crystals act as the ultra-hard cutting medium.
Flexible Backing: The diamond particles are attached to a cloth or plastic film substrate using resin or metal binders (such as electroplated nickel).
Elastic Grinding: Unlike rigid diamond grinding wheels, a belt offers flexible contact that easily conforms to complex contours, curves, and edges.
Hard Materials: Used on ultra-hard, brittle materials like glass, ceramics, stone, crystal, and composite materials.
Industrial Sectors: Essential in aerospace manufacturing, glass processing, and advanced material laboratories for stock removal and fine finishing
Material Type: Diamond wheels are not measured by Rockwell steel hardness scales because they are
not recommended for grinding ferrous metals (steels/iron). High heat at the grinding interface causes carbon in the diamond to chemically react with iron, destroying the abrasive.
Proper Application: Diamond is reserved for hard, brittle, non-ferrous materials such as
tungsten carbide (often 80–90 HRA), glass, ceramics, and stone
CUBIC BORON NITRIDE:
(CBN) is
a synthetic superhard material made of boron and nitrogen atoms arranged in a cubic crystal structure, known as the second-hardest material in the world after diamond
Key Properties
Extreme Hardness: Ranks just below diamond on the hardness scale.
Thermal Stability: Withstands temperatures above 800°C without losing structural integrity.
Chemical Inertness: Resists reacting with iron and other ferrous metals, unlike diamond.
CBN 2x72 belts excel exactly where standard belts fail: working on
hardened ferrous metals (above 55–80 HRC) while generating minimal heat.
When to Use CBN 2x72 Belts
- Post-Heat-Treat Bevel Grinding:
Standard ceramic belts glaze over or dull rapidly when trying to grind clean bevels into hardened steel. CBN cuts through 60–80 HRC steel with ease.
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Grinding High-Vanadium Super-Steels: Advanced alloys like
Maxamet,
Rex 121,
CPM-10V, S90V, or Magnacut feature vanadium carbides that are harder than the aluminum oxide or ceramic grains on standard belts. CBN is one of the few abrasives hard enough to clean up these steels efficiently.
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Precision Sharpening and Honing: CBN 2x72 belts in fine micron or grit sizes provide a razor-sharp, highly durable edge on premium cutlery or wood-turning gouges without drawing the temper of the steel.
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Crisp Plunge Lines and Flats: Because high-quality CBN belts feature a very stiff, dimensionally stable backing (often a flexible metal or heavy polyester core), they do not sag or track erratically. This allows for surgically flat grinds and crisp plunge lines.
When NOT to Use CBN Belts
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Profiling Raw Steel Blanks (Soft Steels): Do not use CBN to profile a knife blank out of unhardened or annealed steel. The gummy, soft steel will immediately clog (load) the spaces between the CBN crystals, ruining an expensive belt. Use a cheap 36-grit ceramic belt instead.
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Wood, Plastics, and Composites: CBN will not cut wood, Kydex, Micarta, or G10 efficiently. The synthetic resins and wood fibers will glaze the belt instantly. Use aluminum oxide for these materials.
- Non-Ferrous Brittle Materials: If you are grinding tungsten carbide coatings, ceramics, or glass, do not use CBN. Switch to
Diamond 2x72 belts.
Best Practices for 2x72 CBN Belts
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Run at Slower Speeds: Unlike ceramic belts that require high speeds and high pressure to break the grains and self-sharpen, CBN cuts optimally at lower RPMs. Dial your VFD (Variable Frequency Drive) down to roughly
30% to 50% speed to avoid friction spikes and maximize belt life.
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Light Pressure is Key: Let the super-abrasive do the work. Pressing heavily against a CBN belt can tear the crystals right out of the bond layer or snap the belt.
- Use Dedicated Cleaning Blocks: Keep a rubber belt-cleaning stick nearby to frequently pull out any minor metal loading and keep the CBN crystals exposed
