HSS M2 vs M35 Cobalt Drill Bits: Which Should You Choose?

What M2 and M35 Mean

HSS (High-Speed Steel) twist drill bits are the workhorse of metal drilling, but not all HSS is equal. The two grades buyers ask about most are M2 and M35 — and the difference decides whether your bit burns out or lasts.

Why Cobalt Matters for Stainless Steel

Both follow the DIN338RN standard. M2 contains about 5% molybdenum and 4% chromium — a versatile, economical bit for carbon steel, aluminium and general alloys. M35 adds about 5% cobalt, which raises red-hardness: the bit stays hard at the high temperatures stainless steel generates. That is why M35 is the default choice for stainless steel and other hard-to-machine metals.

Quick Decision Rule

• Drilling mild steel, aluminium, wood, plastic → M2 (e.g. FANXI 900 DIN338RN M2 Bright, or 910 M2 TiN-coated for longer life).

• Drilling stainless (inox), cast iron, hardened steel → M35 (e.g. FANXI 990 DIN338RN M35 Amber, or 992 M35 with CrTiAlN coating for maximum heat resistance).

Tips That Double Bit Life

Use cutting fluid on stainless, keep RPM moderate, and let the flutes clear chips. A cobalt bit costs more upfront but avoids the "burned tip after three holes" failure that wastes more time than money.

FANXI HSS Range

900/910 (M2 Bright/TiN), 990/992 (M35 Amber/CrTiAlN), plus 902 DIN1897RN short series and 917 extra-long. All DIN338RN, bulk or OEM.

Need a stainless-grade sample? Email vincent@lutools.com or WhatsApp +86 153 3654 3580.