13PCS HSS-Cobalt Drill Bits (M35) — Three-Flute, 135° Split Point, 1/16"–1/4"

For Hard Metal, Hardened Stainless Steel, and Cast Iron • Jobber Length • Round Shank

Built for difficult jobs, this 13-piece M35 cobalt HSS (≈5% Co) set uses a three-flute twist plus a 135° split point to bite instantly, self-center, and hold a stable path through hardened stainless, cast iron, and alloy steels. Fully-ground bodies control runout for rounder holes and longer life. Jobber-length round shanks fit any 3-jaw chuck; a compact metal index case keeps the kit organized.

Why this set wins on hard materials

Three-flute stability: Extra land support reduces chatter and ovality; chips break smaller—ideal for cast iron and austenitic stainless.

135° split-point: Self-centers, reduces walking on curved/painted surfaces, lowers thrust at breakthrough.

M35 cobalt core: High red-hardness maintains a sharp edge at temperature; optional TiAlN/AlTiN coatings for extreme duty.

Precision-ground flutes: Better concentricity and smoother chip evacuation = cleaner holes and fewer regrinds.

Pro tip: On stainless and deep holes, run lower RPM with cutting oil and peck to manage heat and chips.

Expanded, search-intent–friendly applications

Automotive/MRO: Drilling out broken studs/bolts (extractor prep), exhaust/manifold brackets, chassis/frame work, stainless trim, accessory mounts.

Fabrication/Metalwork: Fixture plates, angle/channel, enclosure panels, tap-drill pilots for threading hard steels.

Cast Iron Components: Gearbox housings, pump bases, machine feet—controlled entry/exit with reduced edge chipping.

Electrical/HVAC: Panel knockouts (pilot), stainless cabinets, bracket and conduit mounts.

Maintenance Teams: Plant repairs on alloy steel frames, guard rails, tool steel fixtures (when hardness permits).

Product Specifications

Size Map with Overall Length (OAL) & Flute Length (FL) — 13 pcs (Inch)

Quick speed & coolant guide (rule-of-thumb)

Packaging & OEM

Indexed case (metal/ABS), retail sleeve + barcode; master cartons for distributors.

Private label: laser-etched logo, custom size maps, coatings, bilingual EN/RU labels & spec sheets.

FAQ

Q1: Three-flute vs. two-flute — what’s the benefit?
The third flute adds rigidity and reduces chatter, producing rounder holes and smaller chips in hard materials; feed rates may be slightly lower than 2-flute in deep drilling.

Q2: Will these handle hardened stainless?
Yes. Use lower RPM, cutting oil, and peck cycles. For extreme hardness (>HRC 45), consider M42 cobalt.

Q3: Impact-driver compatible?
Round shanks are for 3-jaw chucks. Ask for hex-shank versions if needed.

Q4: Can I get TiAlN coating?
Yes—TiAlN/AlTiN coatings are available for higher heat resistance and dry cutting.