CNC Bit Reference — Genmitsu MC40A — Flat Downcut 2-Flute (Nano Blue)

Downcut pushes chips down into the cut — top face of the workpiece stays crisp and splinter-free. Trade-off is reduced chip clearance; chips pack into the slot if DOC is too deep. Feeds & Speeds (Wolfpawn 4040 Pro, 3.175mm cutting dia): RPM: 10000 Feed rate: 600–900 mm/min (slower than upcut — chip clearance limited) Depth of cut: 0.8–1.0mm per pass max Plunge rate: 200 mm/min Best for: Veneered plywood (top face must be clean) Painted or primed MDF signs Surface engrave operations where tearout ruins the job Not ideal for: Deep pocketing — chips pack in Through cuts on thick stock alone — combine with upcut pass Specs Limits Applications Settings Tips For through cuts: use downcut for first pass (top face), upcut for remaining depth. Shallow DOC is essential — 0.8mm or less per pass to avoid chip compaction and heat.