Screw Pitch Gauges

Screw Pitch Gauge Range — Quick Reference

Screw pitch gauges are leaf-style gauges for identifying thread pitch on unknown screws, bolts and fittings. Run each leaf across the thread until you find the one that seats perfectly with no rocking or gap — that's your pitch. Critical for matching replacement fasteners, selecting correct taps, and confirming fitting compatibility. AIMS stocks gauges across all common Australian thread standards.

How to use: seat the gauge leaf into the thread peaks; if the leaf rocks or shows gaps between teeth, try the next pitch. The correct gauge will sit flat with all teeth engaged. For matching taps once pitch is identified, see taps. For thread chasing on damaged external threads, see die nuts. For broader background, see our threading tap size chart.

Screw Pitch Gauges for Thread Identification in Australian Workshops

Screw pitch gauges are the precision-formed leaf gauges used to identify thread pitch on screws, bolts, and threaded components. For Australian fitters, mechanics, and toolroom workers handling unidentified or replacement threaded components, a pitch gauge is the fastest path to confirming the right thread for replacement, matching tap, or compatible fitting. AIMS Industrial stocks screw pitch gauges across metric, imperial, and pipe thread standards.

The pitch gauge types we stock

• ISO metric pitch gauges — for metric coarse and fine pitches (the everyday workshop standard)
• UN/UNF/UNC pitch gauges — for American imperial threads
• BSW (Whitworth) pitch gauges — for British heritage imperial threads
• BSP/BSPT pitch gauges — for pipe threads
• Combination gauges — multiple thread standards on one fan-handle gauge

How pitch gauges work

Each leaf in the gauge has a precision-formed thread profile matching a specific pitch. To identify a thread, place the gauge against the thread and check for full engagement — the gauge profile should mate cleanly with the thread crests and roots, with no visible gap. The matching pitch is the one printed on that leaf. For external threads, place the gauge over the threads; for internal threads (in tapped holes), use small-tip gauges that fit into the bore.

Where pitch gauges earn their place

• Thread identification on unmarked components — confirming the pitch of a threaded shaft, fastener, or fitting
• Replacement fastener sourcing — confirming the existing thread before ordering replacements
• Tap selection — verifying the tapping drill and tap size for thread cutting
• Cross-reference between thread standards — checking whether a thread is metric, UN, BSW, or BSP
• Quality control — verifying threads on production parts

Common thread standards in Australian workshops

• ISO metric coarse — the dominant standard in modern Australian engineering and manufacturing
• ISO metric fine — used in specific high-stress and precision applications
• UNC and UNF — common in US-origin equipment, automotive, and aerospace
• BSW (Whitworth) — heritage British equipment, restoration work, older machinery
• BSP and BSPT — Australian plumbing and hydraulic threads
• NPT — US pipe threads, found in imported plumbing and pneumatic equipment

Care and accuracy

Pitch gauges are precision tools. Store them in their case or roll, keep clean and lightly oiled to prevent rust, and inspect leaf edges before relying on the readings. Damaged or bent leaves give false readings. For traceable inspection workplaces, periodic calibration may be required as part of the broader measuring tool calibration regime.

Companion ranges at AIMS

Screw pitch gauges sit alongside our broader measuring tools range — see measuring tools, radius gauges, metric hand taps, and protractors for the related products.

Need help matching pitch gauges to specific thread standards or workshop work? contact our team — we'll match by thread system and resolution.