British Standard Square and Hexagon Bolts

British Standard Square and Hexagon Bolts, Screws and Nuts.—Important dimensions of precision hexagon bolts, screws and nuts (BSW and BSF threads) as covered by British Standard 1083:1965 are given in Tables 1 and 2. The use of fasteners in this standard will decrease as fasteners having Unified inch and ISO metric threads come into increasing use.

Dimensions of Unified precision hexagon bolts, screws and nuts (UNC and UNF threads) are given in BS 1768:1963 (obsolescent); of Unified black hexagon bolts, screws and nuts (UNC and UNF threads) in BS 1769:1951 (obsolescent); and of Unified black square and hexagon bolts, screws and nuts (UNC and UNF threads) in BS 2708:1956 (withdrawn). Unified nominal and basic dimensions in these British Standards are the same as the comparable dimensions in the American Standards, but the tolerances applied to these basic dimensions may differ because of rounding-off practices and other factors. For Unified dimensions of square and hexagon bolts and nuts as given in ANSI/ASME B18.2.1-1996 and ANSI/ASME B18.2.2-1987 (R1999).

ISO metric precision hexagon bolts, screws and nuts are specified in the British Standard BS 3692:1967 (obsolescent) (see British Standard ISO Metric Precision Hexagon Bolts, Screws and Nuts), and ISO metric black hexagon bolts, screws and nuts are covered by British Standard BS 4190:1967 (obsolescent).

British Standard Screwed Studs.—General purpose screwed studs are covered in British Standard 2693: Part 1:1956. The aim in this standard is to provide for a stud having tolerances which would not render it expensive to manufacture and which could be used in association with standard tapped holes for most purposes. Provision has been made for the use of both Unified Fine threads, Unified Coarse threads, British Standard Fine threads, and British Standard Whitworth threads as shown in the table on page 1573. Designations: The metal end of the stud is the end which is screwed into the component. The nut end is the end of the screw of the stud which is not screwed into the component. The plain portion of the stud is the unthreaded length.

In general, it will be found that the amount of oversize specified for the studs will produce a satisfactory fit in conjunction with the standard tapping as above. Even when interference is not present, locking will take place on the thread runout which has been carefully controlled for this purpose. Where it is considered essential to assure a true interference fit, higher grade studs should be used. It is recommended that standard studs be used even under special conditions where selective assembly may be necessary.

British Standard Whitworth (BSW) and Fine (BSF) Precision Hexagon Bolts, Screws, and Nuts

Table 1. British Standard Whitworth (BSW) and Fine (BSF) Precision Hexagon Slotted and Castle Nuts BS 1083:1965 (obsolescent)

Table 2. British Standard Whitworth (BSW) and Fine (BSF) Precision Hexagon Slotted and Castle Nuts BS 1083:1965 (obsolescent)

Table 3. British Standard ISO Metric Precision Hexagon Bolts, Screws and Nuts

BS 3692:1967 (obsolescent)

Table 4. British Standard ISO Metric Precision Hexagon Bolts and Screws BS 3692:1967 (obsolescent)

Table 5. British Standard ISO Metric Precision Hexagon Nuts and Thin Nuts BS 3692:1967 (obsolescent)

You may see also the other related topics:

Metric Threaded Fasteners - List of Standard ANSI for Metric Screws

Unified Screw Threads - American Standard for Unified Screw Threads

Engineering Books - Mechanical Engineering Books

Considerations in Machine Design Materials

Considerations in Machine Design Materials

   After the general layout of the machine has been determined and the necessary mechanisms chosen or devised, it becomes necessary that the designer select a proper material for each machine member. This involves the consideration of such factors as the engineering properties of the available materials; weight, size and the shape of the machine member as well as the loads that it must carry; cost of the material; cost of fabricating the machine element from each material, usually with several alternative production procedures possible for each material; and any properties of the material peculiar to the use to which the member will be put.

   The major engineering properties of materials which important to designer is the strength, stiffness, ductility, toughness, resilience, fatigue resistance, shock resistance, wear resistance, hardness, machinability, effects of high and low temperature, visual appearance and vibrational properties.

The Designer

The Designer

   As the designer develops his idea into finished plans for a machine, he must bring into play an extensive knowledge of subjects that may be roughly classified as; Technical factors, Experience factors and the Human factors.

   The technical information necessary to design a machine varies with the type and field of application; and no one designer can become expert in all types of design. However, an understanding of mechanisms, mechanics, structures, materials, mechanical processes, fluid mechanics, thermodynamics, electrical circuits, and similar technical subjects is essential to every type of design. Since the stresses and the deflections in all parts of a machine cannot always be accurately determined, the designer is forced to rely upon experimental data. The ability to analyze and use of experimental data is a very important characteristic of the designer.

Machine Design Philosophy

Design

  Engineering design is the culmination of an engineering education. Without design, industry would have no new or improved products, basic information resulting from research would not be put to the use of man, and progress would halt. Engineering design is found in all professions and specialties - medicine, chemistry, architecture, and so on. Design is a dynamic field and includes various types of designers. In industry one finds product designers, appearance designers, apparatus designers, industrial designers, machine designers, system designers, tool designers, electrical circuit designers, structural designers, creative designers, and others. 

  Engineering is the art and science by which the properties of matter and the sources of power in nature are made useful in structure, machines and fabricated parts.