BS 1580-3:2007

BS 1580-3 specifies limits of sizes, and tolerances, for single-start, clearance-fit unified screw threads, in inch units with diameters below 1/4 in.

BS 1580-3 specifies unified screw threads from Number 0 (0.060 in diameter) to Number 12 (0.216 in diameter), known as the “numbered sizes” in the following standard series:

• a coarse thread (UNC) series
• a fine thread (UNF) series
• for Number 12 threads, an extra fine (UNEF) 32 threads per inch diameter/pitch combination.

This part of BS 1580 is intended for use with BS 919-1 which specifies the corresponding screw gauges.

BS 1580-3 contains:

• Normative references
• Terms and definitions and symbols
• Thread profiles
• Diameter/pitch combinations
• Tolerance classes
• Tolerances, allowances and limits of size for uncoated threads
• Coated threads
• Designation of threads
• Gauges

BS 1580-3:2007 supersedes BS 1580-3:1965, which is withdrawn.