Piikkimittarit

Piikkimittarit, or spike gauges, constitute a family of precision measuring instruments used to determine the size and tolerances of spike- or needle-like features in mechanical components. They are employed in manufacturing, inspection, and quality control to verify dimensions of pins, studs, teeth, or other protruding features where accurate cross-sections or spacing must be within specified limits.

Designs vary: many sets consist of a collection of calibrated pins of precise diameters arranged in a holder; others are go/no-go gauges with fixed internal or external dimensions. Materials typically include hardened steel or carbide for wear resistance. Sizes are usually specified in metric or imperial units, and tolerances range from a few micrometers in small sizes to larger values for bigger gauges. Some sets are modular, allowing rapid selection of multiple sizes.

Usage involves selecting gauges that correspond to the specification. A go gauge is expected to pass with slight clearance, while a no-go gauge should not pass. This allows inspectors to quickly confirm whether a feature falls within the allowed range. The method is comparative and does not measure an exact value beyond whether it fits within the designated tolerance.

Applications extend across tooling, automotive, aerospace, electronics, and general mechanical engineering, where precise control of small diameters and spacings is essential. Piikkimittarit complement other gauges such as calipers, micrometers, and plug gauges in a measurement toolkit.

Finnish term: piikkimittarit translates roughly to spike gauges, derived from piikki (spike) and mittari (gauge).