Precision Grinding Operations
Grinding wheel bonds, grit numbers, dressing, wheel safety, magnetic chucks, glazing causes, and grade selection.
- Identify grinding wheel bond types and grit numbering systems
- Describe wheel dressing procedures and mounting safety
- Explain glazing causes, magnetic chuck operation, and wheel grade selection
Leçon 1
Grinding Wheel Bonds & Grit Numbers
Grinding Wheel Marking System
Every grinding wheel has a standardized marking system that identifies its composition. A typical marking reads: A 60 K 5 V
| Position | Example | Meaning |
|---|---|---|
| 1 - Abrasive type | A | A = Aluminum oxide, C = Silicon carbide |
| 2 - Grit size | 60 | Coarseness (higher = finer) |
| 3 - Grade | K | Hardness of bond (A = soft, Z = hard) |
| 4 - Structure | 5 | Grain spacing (1 = dense, 15 = open) |
| 5 - Bond type | V | V = Vitrified, B = Resinoid, R = Rubber |
Abrasive Selection
Aluminum Oxide (A)
Color: Brown, white, or pink
Grinds: Carbon steel, alloy steel, HSS
Property: Tough, fracture-resistant
Most common abrasive overall
Silicon Carbide (C)
Color: Black or green
Grinds: Cast iron, brass, aluminum, stone
Property: Sharper, more brittle
Best for non-ferrous and brittle materials
Grit Size
The grit number indicates the number of openings per linear inch in the screen used to size the grains:
- Coarse (16-30) - heavy stock removal, soft materials
- Medium (36-60) - general purpose grinding
- Fine (80-120) - finishing and precision work
- Very fine (150-600) - lapping, honing, polishing
Aluminum oxide (A) is used for steel. Silicon carbide (C) is for cast iron and non-ferrous metals. Vitrified (V) is the most common bond. Higher grit numbers mean finer grain and smoother finishes.