Edge prep affects insert toughness, cutting forces, and tool life. Choosing wrong reduces tool life by 50-70%.
Sharp Edge (No Prep)
Cutting edge formed exactly where the rake and flank faces meet — no rounding.
- Best for: Light finishing, aluminum, copper, plastics
- Avoid for: Hardened steel, interrupted cuts, scaled materials
- Tool life: Shortest in heavy cuts (chip easily)
Honed Edge
Cutting edge slightly rounded, typically 25-50 µm radius.
- Best for: General-purpose milling and turning, most steel grades
- Pros: Reduces edge chipping, balances toughness and sharpness
- Cons: Slightly higher cutting forces vs sharp
T-Land Edge
Negative chamfer ground on the rake face at 25-45° × 0.05-0.20mm wide. Reinforces edge.
- Best for: Heavy roughing, interrupted cuts, hardened materials
- Pros: Strongest edge, withstands impact
- Cons: Higher cutting forces, requires more spindle power
Chamfer + Hone
T-land plus a hone radius on the cutting edge. Most production-friendly combination.
- Best for: Production turning of steel and stainless
- Pros: Combines impact resistance with smooth cutting
Application Selection
| Application | Edge Prep |
|---|---|
| Aluminum finishing | Sharp (no prep) |
| Steel turning, general | Honed (25 µm) |
| Steel roughing | T-land 25° × 0.1mm |
| Stainless turning | Honed (35-50 µm) |
| Cast iron | T-land 25° × 0.15mm |
| Hardened steel turning (CBN) | T-land 30° × 0.1mm + hone |
| Interrupted cuts | T-land 35° × 0.2mm |
| Threading | Sharp (no prep) for full profile |
| Aerospace titanium | Honed only (no chamfer — high cutting forces) |
Insert Catalog Codes
Manufacturers code edge prep in insert designation:
- F suffix — Finishing edge prep (sharp/light hone)
- M suffix — Medium prep (general use)
- R suffix — Roughing prep (T-land + hone)
- WMR / WMX — Wiper variants with reinforced edge
If Edge Prep Wrong: Symptoms
- Sharp edge breaking in interrupted cuts → switch to honed or T-land
- Honed edge in light finishing causing rubbing → switch to sharp
- T-land in stainless causing high forces and BUE → switch to honed
For grade + edge prep matching, see coating selection guide.
Shop Related Products at HOOGUU
