Screw Thread Micrometer
Product Specifications:
This series is available in 20 model variants (125-101 through 125-120). Exact pitch range, accuracy, and anvil interchangeability per variant are needs verification against the Mitutoyo datasheet for each specific model code.
A screw thread micrometer is a specialized micrometer used to measure the pitch diameter of external threads. It uses shaped measuring anvils that seat into the thread profile, unlike a standard micrometer’s flat measuring faces.
Screw Thread vs Standard Micrometer
Screw thread micrometers use V-shaped and cone-shaped anvils that seat into a thread’s profile rather than flat measuring faces. Pitch diameter, not outside diameter, is the key dimension a screw thread micrometer is designed to measure. Thread micrometers are typically supplied with interchangeable anvils to match different thread pitches.
Applications
Screw thread micrometers are used in machine shops and thread-manufacturing QA to verify threads meet drawing tolerances. See BTSA’s guide to thread types in metrology and BTSA’s calibration services for thread micrometer calibration.
Frequently Asked Questions
How is a screw thread micrometer different from a standard micrometer?
A screw thread micrometer has specially shaped anvils that seat into a thread’s profile to measure pitch diameter, while a standard micrometer has flat anvils for measuring outside diameter or thickness.
What does a screw thread micrometer measure?
It measures the pitch diameter of an external thread, a key dimension used to verify that a threaded part meets its drawing tolerance.
Does a screw thread micrometer work on internal threads?
Screw thread micrometers are generally designed for external threads; internal thread measurement typically requires different gauging methods such as thread plug gauges. Needs verification — confirm this model’s intended use case.
What thread pitches can this micrometer measure?
This series is available in 20 model variants (125-101 through 125-120). Needs verification — confirm the specific anvil/pitch range per variant from the product datasheet before publishing as a firm spec.
How is pitch diameter different from outside diameter on a thread?
Pitch diameter is measured at the point on the thread where the width of the groove equals the width of the thread itself, which is different from the thread’s overall outside diameter.
How often should a screw thread micrometer be calibrated?
Calibration frequency depends on usage and your quality system’s requirements. BTSA operates NABL-accredited calibration services in Chennai and Hyderabad.
Want to understand pitch diameter measurement in more depth? See our guide What Is a Thread Micrometer? How It Measures Pitch Diameter.
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