helixhoek

Helixhoek, or helix angle, is a geometric property of a helix on a cylindrical surface. In engineering, it describes the steepness of a screw thread and the orientation of teeth on helical gears. The term is used in Dutch-language technical literature and is defined with context-specific meaning.

For screws and threaded fasteners, the helix angle at the pitch diameter is the angle between the helix and a plane perpendicular to the axis, also called the lead angle. If L is the lead per revolution and d is the pitch diameter, then tan(λ) = L / (π d). The lead L equals the thread pitch times the number of starts; a multi-start thread has a larger lead and a larger helix angle.

In helical gears, the helix angle β is the angle between the tooth trace and the gear axis, measured on the pitch cylinder. It affects axial thrust, contact pattern, and load distribution. Higher β increases axial forces and changes efficiency; typical gear designs use β in a range that depends on the application, often around 15° to 30°.

Measurement and application: Helix angles are specified during design and verified with measurement tools; manufacturing tolerances influence the actual helix angle. The concept is central to fasteners, leadscrews, and power-transmission gears, where the helix angle determines how motion is converted between rotational and linear directions and how forces are transmitted along the axis.