4.1.1 Drawing proportions

Bolts and screws

Studs

Standard nut

Thin (lock) nut

Plain washer

4.1.2 Alternative screw heads

4.1.3 Alternative screw points

4.1.4 Hexagon socket cap head screw

4.1.5 Applications of screwed fasteners

4.1.6 Acme thread form

4.1.7 Square thread form

4.1.8 Buttress thread form

4.1.9 V-thread form

4.1.10 Basic Whitworth (55 ) thread form: parallel threads

This is the basic thread form for BSW, BSF and BSP screw threads.

4.1.11 ISO metric and ISO 60 unified thread forms

4.1.12 Introduction to screwed fasteners

Although dimensioned in inch units the following screw thread tables (Sections 4.1.38 to 4.1.43) have been retained for maintenance data and similar applications. Screwed fasteners to these specifications are still manufactured:

• 4.1.38 British Standard Whitworth (BSW) bolts and nuts

• 4.1.39 British Standard Fine (BSF) bolts and nuts

• 4.1.40 ISO unified precision internal screw threads: coarse series (UNC)

• 4.1.41 ISO unified precision external screw threads: coarse series (UNC)

• 4.1.42 ISO unified precision internal screw threads: fine series (UNF)

• 4.1.43 ISO unified precision external screw threads: fine series (UNF)

Although obsolescent the following screw thread table (Section 4.1.45) has been retained for the reasons given above:

• 4.1.45 British Association (BA) internal and external screw threads

The tables based on abstracts from the BS EN 24000 series have been replaced by the current BS EN ISO 4000 series for screwed fasteners with metric dimensions. These new standards (Sections 4.1.13 to 4.1.21) are as follows:

• 4.1.13 BS EN ISO 4014: 2001 Hexagon head bolts product grades A and...