A center hole grinding stone is a specialized abrasive tool used for precision grinding of center holes (also known as center drills or countersinks) in workpieces, typically for lathe or cylindrical grinding applications. These stones are designed to maintain accurate angles (usually 60°) and smooth finishes in center holes, ensuring proper alignment and reduced runout during machining.
Key Features:
1. Material:
– Made from aluminum oxide (common) or silicon carbide for hard materials.
– May include diamond or CBN (cubic boron nitride) coatings for ultra-hard alloys.
2. Shape & Size:
– Conical or cylindrical shape with a tapered tip matching standard center hole angles (60° is most common).
– Available in various grits (fine to coarse) for roughing or finishing.
3. Applications:
– Reconditioning worn center holes.
– Precision grinding of lathe centers, tailstock centers, or workpiece centers.
– Used in toolroom grinding, aerospace, and automotive industries.
4. Mounting Options:
– Fits bench grinders, tool post grinders, or specialized center hole grinding machines.
– Some stones are mounted on arbors for rotary tools.
Usage Tips:
– Speed: Operate at recommended RPM to avoid overheating.
– Coolant: Use cutting fluid (if applicable) to extend stone life and improve finish.
– Dressing: Regularly dress the stone with a diamond dresser to maintain shape and sharpness.
Common Standards:
– Angle: 60° (ISO/B&S standard), 75° (less common).
– Grit Range: #80–#220 for general use; finer grits (#400+) for high-precision work.
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