Differences Between Type N, Type H, Type W

The helix angle of a high-speed steel (HSS) drill bit is a critical factor that affects its cutting performance and is chosen based on the material being drilled. There are three common types of HSS drill bits categorized by their helix angle: Type N, Type W, and Type H. Each type is suited for drilling different materials. Here’s a detailed look at these types and their typical helix angles:

Type N Drill Bit

1.Helix Angle: Medium Helix Angle: Typically around 20° to 30°.


General Purpose: Suitable for drilling a wide range of materials including steel, cast iron, and non-ferrous metals.

Balanced Performance: Provides a good balance between cutting efficiency and chip removal.


Chip Removal: Moderate chip removal capacity, ideal for general use.

Versatility: The most common type, used in many standard drilling applications.

hss drill bit

Type W Drill Bit

1.Helix Angle: Large Helix Angle: Typically around 35° to 40°.


Soft and Ductile Materials: Designed for drilling soft materials such as aluminum, copper, and soft plastics.

Aggressive Cutting: The larger helix angle allows for more aggressive cutting and efficient chip removal.


Chip Removal: Excellent chip evacuation, preventing clogging in softer materials.

Surface Finish: Provides a smoother surface finish due to efficient chip clearance.

Type H Drill Bit

1.Helix Angle:

Small Helix Angle: Typically around 10° to 20°.


Hard and Brittle Materials: Suitable for hard materials like stainless steel, hardened steels, and some high-temperature alloys.

Controlled Cutting: The smaller helix angle reduces the cutting forces, preventing premature wear and breakage.


Chip Control: Produces shorter chips, which helps in managing brittle materials.

Durability: Increased durability and reduced wear when drilling hard materials.

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Post time: May-14-2024