Machine Drawing

168 Machine Drawing

dharm
d:\N-Design\Des11-1.pm5

a 5 300 z 7 300

a

z

z=a 2

s l s l

(a) For symmetrical welds only

(c) To be welded on the other side

(b) To be welded on the arrow side

Fig. 11.8 Position of the symbol

11.3 Dimensioning of Welds

Each weld symbol may be accompanied by a

certain number of dimensions. These dimensions

are written as indicated in Fig. 11.9. It shows (i)

the main dimensions relative to the cross-section,

written on the left hand side of (before) the

symbol and (ii) longitudinal dimension written

on the right hand side of (after) the symbol.

NOTE The absence of any indication fol-

lowing the symbol, signifies that the weld is to

be continuous over the whole length of the work

piece.

11.3.1 Dimensioning Fillet Welds

There are two methods to indicate the dimensions

of fillet welds as shown in Fig. 11.10. The letter

a (throat thickness), or z (leg length) is always

placed in front of the value of the corresponding

dimension.

11.4 Edge Preparation of Welds

The contours of edge preparation for butt welds are shown in Fig. 11.11.

The method of indicating the main dimensions and the rules for setting down these

dimensions are illustrated in Table 11.5.

Fig. 11.9. Dimensioning of welds

Fig. 11.10 Dimensioning-fillet welds