Starrett 575AP Screw Thread Micrometer 0-1" Range 7-9 TPI Pitch Diameter Gauge

The Starrett 575AP Screw Thread Micrometer is a precision hand tool engineered for accurately measuring the pitch diameter of screw threads. With a 0–1" measuring range and coverage of 7–9 TPI (threads per inch), it is ideally suited for coarse-thread fasteners and components in the American Unified National and Unified J series standards.

At the heart of this micrometer is a pointed conical spindle and double V-anvil, both precisely shaped to seat directly into the thread form. This geometry ensures the measurement reflects the true pitch diameter — not the crest or root of the thread — delivering results with a resolution of .001".

Key Features:

• Measuring range: 0–1" with .001" graduation
• Thread pitch coverage: 7–9 TPI
• Pointed spindle and double V-anvil contact geometry for direct pitch diameter measurement
• Anvil and spindle constructed of hardened steel for long-term durability
• Fixed, non-rotating anvil for consistent, repeatable measurements
• One-piece drop-forged steel frame for rigidity and stability
• Tapered frame design accesses narrow slots and confined spaces
• Advanced sleeve design with staggered lines and distinct figures for clear readability
• No-glare Starrett satin chrome finish resists rust and reduces eye fatigue
• Design provides 50–75% contact with the thread, ensuring contact at the pitch diameter at all times
• Balanced frame for comfortable, accurate hand-held measuring
• Includes a one-inch standard at no extra cost
• Compatible with American Unified National series and Unified J series screw threads

The Starrett 575AP is a trusted choice for machinists, quality control inspectors, and toolroom professionals who require reliable, repeatable pitch diameter measurements on coarse-pitch threaded parts.