CONVENTIONAL DRAWING OF FIXINGS AND JOINTS

The conventional drawing of fixings (table 4.11) is regulated by State Standard 2.315:2008. Fixings for which on a drawing the diameter of a bar is equal 2 mm or less is shown conventionally. Conventional drawing and its sizes must give exhaustive and necessary information about the view of a joint and its components.

Table 4.11 - The conventional drawing of fixings

Name of a part	View	Drawing	Name of a part	View	Drawing
Round-head and cheese-head bolts and screws	Main (front)		Nuts	Main (front)
Top		Top
Bottom	·	Washers	Main (front)
Countersunk-head and oval-head screws	Main (front)		Top
Top		Studs	Main (front)
Bottom	·	Top	·

In fig.4.25 the examples of conventional drawings of thread joints are resulted: a – by a bolt on a view and in a section; b – by a stud on a view and in a section; c – by a countersunk-head screw on a view and in a section; d –by a cheese-head screw on a view and in a section.

а) b) c) d)

Figure 4.25 – Conventional drawings of thread joints

PIPE JOINTS

Pipes are used to carry steam, water, gas, oil and many other fluids. The pipes for a particular use cannot be made of desired length. Therefore pipes of standard length are taken and joined together with the help of pipe joints of different types. Normally the pipes are made of cast iron, steel, copper and wrought iron, depending upon te pressure and temperature of the fluid to be conveyed.

A pipe cylinder or a conical thread is used for pipe joints. All parameters, including external diameter of a pipe thread, are determined according to conventional nominal sizes of thread in inches, which correspond the diameter of a pipe opening (in inches), if a thread is cut at the external surface of a pipe.

Thus, the external diameter of a pipe thread is always greater (fig. 4.5) than the conventional nominal size on two thickness of a wall pipe. Parameters of a pipe thread resulted in table 4.12.

It should be remembered, that an opening diameter in a pipe depends on the accuracy of its manufacturing and approximately corresponds the conventional nominal size of a thread in inches (1inch =25,4mm).