Crossdrill

Crossdrill, or cross-drilling, is a machining technique in which one or more holes are bored through a component perpendicular to its longitudinal axis, such that the holes pass through or intersect within the cross-section. The result is a crosswise hole pattern that can accommodate fasteners, pins, lubrication channels, or weight-reducing passages. The term is common in mechanical engineering, manufacturing, and precision machining.

Crossdrilling is frequently used on shafts, pins, and linkages to allow the passage of a pin, a set screw, or a lubricant. In engine and hydraulic components, cross-drilled passages enable oil or coolant to reach bearing surfaces or internal cavities. In tooling and fixtures, cross holes can serve as locating pins or drainage passages. The operation is typically performed with care to maintain alignment; locating jigs, accurate workholding, and careful drill geometry are essential. Finishing steps may include deburring, counterboring, or reaming to achieve required tolerances and surface finish.

Design considerations include assessing the impact on strength and fatigue life, especially where holes reduce cross-sectional area. Hole size, spacing, and orientation must avoid stress concentrations and intersect with existing features. Material properties, surface finish, and subsequent heat treatment may influence hole quality and retention of lubricants or fasteners. In some cases, multiple cross-drilled holes are used to create a specific flow path or weight reduction without compromising critical dimensions. Crossdrill patterns vary by application and are often specified in engineering drawings as through-holes or partial-depth holes with precise tolerances.