CNC Bit Reference — Genmitsu MC40A — Ball Nose 2-Flute (Nano Blue)
Ball nose for 3D relief carving, contoured surfaces, and rounded channels.
Feeds & Speeds (Wolfpawn 4040 Pro):
3.175mm cutting dia (finishing): RPM: 10000 Feed rate: 800–1000 mm/min Stepover: 5–15% of diameter (0.15–0.5mm) for smooth finish DOC: 0.3–0.5mm per pass
3.175mm cutting dia (roughing): RPM: 10000 Feed rate: 1000–1200 mm/min Stepover: 40–50% of diameter DOC: 1.0mm per pass
2.0mm cutting dia: RPM: 10000 Feed rate: 400–600 mm/min Stepover: 0.1–0.3mm for fine detail DOC: 0.3mm per pass
Workflow:
- Rough with flat upcut end mill (fast, removes bulk)
- Finish with ball nose (slow, fine stepover)
Skipping roughing wastes time and dulls the ball nose prematurely.
Specs
| Setting | Value |
|---|---|
| Shank | 1/8" (3.175mm) |
| Cutting Dia | 3.175mm (1/8") |
| Flutes | 2 — ball nose |
| Material | Tungsten carbide |
Limits
| Setting | Value |
|---|---|
| Max Rpm | 30000 RPM |
Applications
| Setting | Value |
|---|---|
| Best For | 3D relief carving, curved surfaces, finishing |
Roughing
| Setting | Value |
|---|---|
| Roughing Rpm | 8000-9000 RPM |
| Roughing Feed | 1200-1500 mm/min |
| Roughing Stepover | 30-40% of bit diameter |
Finishing
| Setting | Value |
|---|---|
| Finishing Rpm | 9000-10000 RPM |
| Finishing Feed | 800-1200 mm/min |
| Finishing Stepover | 5-10% of bit diameter |
Tips
Stepover is the dominant variable for surface finish quality — smaller = smoother, longer run time. Check the 3D toolpath preview in Vectric/Fusion for scallop height before running. Tip of ball nose is the most fragile point — avoid full-depth plunges.