See the Thread Identification Presentation here.

See the Bolts Information Handout here.

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Typical Thread Forms Nomenclature

Unified Form – UNC “Unified National Coarse”  UNF  “Unified National Fine”

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Whitworth – BSW “British Standard Whitworth”  BSF “British Standard Fine” 

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British Association – BA (Find out more here)

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Metric Thread Form – Metric Coarse (Standard)  & Metric Fine (Find out more here)

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BSP / BSPT – British Standard Pipe / British Standard Pipe Taper

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Acme Form

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Buttress Form

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Lead Screw Profiles

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How to draw Acme thread