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: 1. Rough with flat upcut end mill (fast, removes bulk) 2. Finish with ball nose (slow, fine stepover) Skipping roughing wastes time and dulls the ball nose prematurely. Specs Limits Applications Roughing Finishing 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.