Hss drill bit

High-Speed Steel (HSS) drill bits are categorized by their alloy composition. HSS-R (Rolled) is suitable for general metalwork, while HSS-G (Ground) offers higher precision and longer life. For industrial applications involving stainless steel or hard alloys, HSS-Co (Cobalt, typically M35 or M42) is essential as it provides superior heat resistance and hardness. M2 (6-5-2) is the global standard for balanced toughness and wear resistance in professional B2B sourcing.

Surface coatings significantly impact friction and durability. Black Oxide provides basic corrosion resistance and lubricity. Titanium Nitride (TiN) coating increases surface hardness and allows for higher cutting speeds, extending tool life by up to 3-4 times. For high-temperature drilling, Titanium Aluminum Nitride (TiAlN) is preferred. Ensure the supplier provides uniform coating thickness to prevent premature peeling during high-torque operations.

Buyers must verify the Shank Type, such as Straight Shank, Taper Shank (Morse Taper), or Hex Shank, to ensure fitment with specific chucks. The Point Angle is also vital; a 118-degree point is standard for general purpose, while a 135-degree split point is better for hard materials as it prevents 'walking' and requires less feed pressure. Always confirm compliance with DIN 338 (jobber length) or DIN 340 (long series) standards.

Request a Rockwell Hardness (HRC) test report. Standard HSS should typically range between 62-65 HRC, while Cobalt grades should reach 66-68 HRC. Additionally, ask for a metallographic analysis to ensure a fine, uniform grain structure, which prevents brittle snapping under load. For large orders, sourcing through Made-in-China.com allows you to filter for suppliers with ISO 9001 certification and verified production capabilities.

The primary risk is material substitution, where a supplier may use low-grade carbon steel labeled as HSS. To mitigate this, utilize Third-Party Inspection services (like SGS or Intertek) to perform random hardness tests at the factory. Another risk is shipping damage; ensure the supplier uses anti-rust oil coating and VCI (Volatile Corrosion Inhibitor) packaging to prevent oxidation during long-term sea freight.

Focus on tiered pricing based on weight and material costs (especially for Cobalt, which fluctuates). For custom branding (OEM), typical MOQs range from 500 to 2,000 pieces per size. Negotiate for sample cost rebates where the sample fee is deducted from the first mass production order. Using Made-in-China.com's Secured Trading services can provide payment protection until the goods pass your quality check.

Ensure the HS Code (typically 820750) is correctly declared to avoid customs delays and ensure accurate duty calculation. For shipping to the US or EU, verify if there are any anti-dumping duties currently active on specific steel products. Always request FOB (Free On Board) terms if you have a preferred forwarder, or CIF (Cost, Insurance, and Freight) if you want the supplier to handle the logistics to your port.