Enter your Nominal Diameter, Thread Pitch, Thread Type, Tolerance Grade, and Tolerance Position into the Thread Calculator to get the Pitch Diameter along with the Major Diameter, Minor Diameter, Thread Height, and complete Thread Designation for your fastener or threaded component.
Pitch Diameter
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Major Diameter
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Minor Diameter
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Thread Height
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Thread Designation
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Threads are helical grooves and ridges wrapped around a cylindrical shaft. They convert rotational motion into linear motion, allowing bolts and nuts to be fastened together with mechanical advantage.
The pitch diameter is calculated as: Nominal Diameter - (0.6495 × Pitch). This is the diameter at the point where the thread thickness equals the groove width.
For external threads: Minor Diameter = Nominal Diameter - (1.2268 × Pitch). For internal threads, it's slightly larger to accommodate tolerances.
External threads are found on bolts and screws, while internal threads are found in nuts and threaded holes. External threads have slightly smaller dimensions to allow proper fit.
Tolerance grades (4-8) indicate how precise the thread dimensions are. Lower numbers mean tighter tolerances and better fit, while higher numbers allow more variation for easier manufacturing.
The nominal diameter is the basic major diameter of the thread - the largest diameter of an external thread or the theoretical diameter before threading for internal threads.
Metric threads are designated as M[diameter]×[pitch]. For example, M10×1.5 means a metric thread with 10mm nominal diameter and 1.5mm pitch between threads.
Thread height is the radial distance from the minor to major diameter. It determines the strength of the threaded connection and affects how much material is engaged between mating threads.