The Anatomy of a Diamond Blade
- THE CORE — the steel disc; it must be balanced (so that vibration is minimal at high speed)
- THE SEGMENTS — a mix of diamond + bond, brazed onto the rim of the core
- THE DIAMOND GRAINS — the element that actually does the cutting (synthetic diamond)
- THE BOND — the metal matrix that holds the diamond grains together (a mix of bronze, iron and cobalt)
Grit Size (Mesh) — Which for Which Material?
| Mesh | Grit Size | Suitable Material | Cut Surface |
|---|---|---|---|
| #30-40 | Coarse | Granite, hard stone | Fast but rough |
| #50-60 | Medium | Marble, travertine | Speed and quality balanced |
| #80-100 | Fine | Engineered stone, precise work | Slow but bright |
| #120+ | Very fine | Glass, grinding | Before polishing |
Bond Hardness
The bond determines how tightly the diamond grains are held. The general rule: HARD MATERIAL → SOFT BOND, SOFT MATERIAL → HARD BOND.
- Soft bond (S) — for granite and hard stone. Worn grains are exposed quickly, so cut quality is sustained.
- Medium bond (M) — the most common choice for marble and travertine.
- Hard bond (H) — for engineered stone and soft stone. The diamond stays usable for longer.
The Consequence of a Wrong Choice
A hard bond on granite → the diamond goes blunt without wearing through, so the blade polishes instead of cutting. A soft bond on marble → the diamond sheds quickly and tool life is short. Advice from the supplier is essential.
Diameter and Segment Height
- Diameter — cutting depth = (blade diameter / 2) - 30 mm. A 400 mm blade → a maximum 170 mm cut.
- Segment height — 8-12 mm on a new blade. REPLACE it when it has dropped to 2 mm (wear on the core begins).
- Segment count — between 16 and 32. A high count gives a clean surface but is slower; a low count is fast but rough.
Speed and Feed Rate
| Blade Diameter | Recommended Peripheral Speed | RPM Calculation |
|---|---|---|
| 350 mm | 40-50 m/s | 2,200-2,700 |
| 400 mm | 40-50 m/s | 1,900-2,400 |
| 500 mm | 35-45 m/s | 1,350-1,700 |
Peripheral speed (m/s) = π × diameter (m) × rpm / 60. High speed → heat and wear increase. Low speed → a matt surface and segment chatter.
Cooling Water — Indispensable!
- A minimum flow of 30 L/min — the blade and the cutting point must stay constantly wet
- Cutting without water is FORBIDDEN — silicosis risk + diamond burning + a poor surface
- Water is sprayed on both sides — it cools the blade core and carries the swarf away
- The cleanliness of the water matters — water high in lime leaves deposits on the blade core
Estimated Blade Life
| Material | Blade Diameter | Estimated Life (linear cutting) |
|---|---|---|
| Marble | 400 mm | 300-500 m |
| Granite | 400 mm | 80-150 m |
| Travertine | 400 mm | 400-700 m |
| Engineered stone | 400 mm | 150-250 m |
| Quartzite | 400 mm | 40-80 m |
Signs of Wear
- Segment height below 2 mm → REPLACE
- The cut is noisy + there is vibration → a segment is cracked or has come off
- Surface quality is deteriorating → the diamond has gone blunt and needs "opening" (1-2 minutes of cutting in soft stone)
- A segment has come off → REPLACE the blade immediately (the core will be damaged)