Twist drill

For industrial applications, the material grade determines the tool's lifespan and heat resistance. HSS (High-Speed Steel) is the standard for general metalworking. For harder materials like stainless steel, you must specify HSS-Co (Cobalt) M35 or M42, which offers superior red-hardness. For high-volume automated production, Solid Carbide is preferred due to its extreme rigidity and wear resistance, though it is more brittle than HSS.

Surface coatings are critical for reducing friction and preventing chip welding. Black Oxide is cost-effective and helps retain lubricants. TiN (Titanium Nitride) provides a gold finish that increases surface hardness and extends tool life. For high-temperature drilling in tough alloys, TiAlN (Titanium Aluminum Nitride) is the premium choice as it forms a protective aluminum oxide layer when exposed to heat.

The Point Angle is crucial: 118 degrees is standard for general-purpose drilling, while 135 degrees (Split Point) is better for hard materials and prevents 'walking' on the workpiece surface. Ensure the Helix Angle (typically 30 degrees) is appropriate for the material being evacuated; a slower spiral is better for brass, while a faster spiral suits aluminum.

Verify that the manufacturer adheres to DIN 338 (Jobber length), DIN 340 (Long series), or ANSI B94.11M standards to ensure dimensional accuracy. For global trade, ensure the supplier is ISO 9001:2015 certified, which guarantees a consistent quality management system during the manufacturing process.

Request a Material Test Report (MTR) or a third-party chemical analysis to confirm the Cobalt or Tungsten content. On Made-in-China.com, prioritize Audited Suppliers whose production facilities have been physically verified by SGS or TÜV Rheinland to ensure they have the heat-treatment equipment necessary for genuine HSS production.

Twist drills are high-volume commodities. Negotiate based on weight-based pricing for bulk orders or tiered unit pricing. If you are a wholesaler, ask for customized laser-marking (OEM) and specialized packaging (e.g., plastic rose boxes or metal cases), which can be negotiated for lower MOQs if you commit to a blanket purchase order with scheduled releases.

Drill bits are heavy and prone to oxidation during sea freight. Ensure the supplier uses VCI (Volatile Corrosion Inhibitor) paper or anti-rust oil coating. For shipping to the US or Europe, specify double-walled corrugated cartons and palletization to prevent box bursting due to the high density of the metal products.

Utilize Secured Trading Services provided by Made-in-China.com to ensure payment is only released after the goods have passed a Pre-Shipment Inspection (PSI). This protects your capital against quantity discrepancies or sub-standard hardness levels that do not match the initial samples.