Bolt Thread Pitch & Diameter Diagram - 1/2 Inch, 20 Threads Per Inch (SAE)

This is a small illustrative diagram explaining how bolt/fastener thread specifications are measured. It depicts a threaded shaft (bolt shank) drawn in profile. Two dimensions are labeled: the "Diameter," indicated as 1/2 inch, measured across the width of the threaded shaft; and the "Pitch," indicated as 20 Threads Per Inch, measured along a marked span of the threads. Together these labels illustrate a 1/2-20 fastener thread specification in the inch (SAE/imperial) system, where pitch is expressed as the count of threads per inch rather than the distance between threads. A reader can learn from this diagram how to identify and read an imperial fastener callout: the first number refers to the major diameter of the threaded portion, and the second number refers to how many thread crests occur in one inch of length. The document contains no vehicle-specific information — no make, model, year, part numbers, or torque values — so it serves as a general hardware/fastener reference. It was uploaded to a 1990 Ford Bronco gallery alongside a related fastener document (acorn/mag/ball lug nut seat styles), suggesting it is part of a general fastener identification reference set.