BS 8666:2000

Table 1 - Standard shapes, their method of measurement and calculation of lengthShape Shape Total length of bar (L)code measured along centre line

00 A

A

11 A A + (B) - 1/2r - d

12

(Bl Neither A nor B shall be less than A in Table 3

A A + (B) - 1/2R - d

(B) Neither A nor B shall be less than A in Table 3nor less than (R + 6d)A + 0.57B + (C) - 1.57d

Neither A nor C shall be less than A in Table 3nor less than (½B + 5d)B shall not be less than 2(r + d)

Neither A nor C shall be less than A in Table 3See note 1

21 A+B+(C)-r-2d

Neither A nor C shall be less than A in Table 325 A+B+(E)

Neither A nor B shall be less than A in Table 3If E is the critical dimension, schedule as 99and specify A or B as the free dimensionSee note 1

6 © BSI 06-2001

BS 8666:2000

Table 1 - Standard shapes, their method of measurement and calculation of length (continued)Shape Shape Total length of bar (L)code measured along centre line

A+B+(C)

Neither A nor C shall be less than A in Table 3

CNeither A nor D shall be less than A in Table 3

33 2A+3B+17d

A

A shall not be less than 12d + 30 mmB shall not be less than 2(r + d)

ASee note 2

41 A A+B+C+D+(E)-2r-4d

444 C Neither A nor E shall be less than A in Table 3

A+B+C+D+(E)-2r-4d

46

C Neither A nor E shall be less than A in Table 3A+2B+C+(E)

Neither A nor E shall be less than A in Table 3See note 1

©BSI 052001 7

BS 8666:2000

Table 1 - Standard shapes, their method of measurement and calculation nf length (continued)Shapecode

51

,Shape Total length of bar (L)

measured along centre line

A 2(A+B+C)-2½r-5d

C

67

4 A C and D shah be equal and not more than A orB nor less than A in Table 3

A A

See clause 10

77 Cp(A - d)

99C= no. of turns

Where B is greater than A/5 this equation nolonger applies and L shall be calculated

All shapes where standard shapes cannot be used. To be calculatedNo other shape code number, form of designationor abbreviation shall be used in scheduling. Withthe exception of rectangular links, 5 bends or moreare undesirable and may be impractical withinpermitted tolerances but they shall be drawn outin full and coded 99.A dimensioned sketch shall be drawn over thedimension columns A to E. Every dimension shallbe specified and the dimension that is to allow forpermissible deviations shall be indicated inparenthesis, otherwise the fabricator is free tochoose which dimension shall allow for thetolerance

For all shapes other than 12,13,33 and 67 the radius of bend shall be not less than the minimum specifiedin Table 3.The dimensions in parentheses are the free dimensions. If a shape given in this table is required but adifferent dimension is to allow for the possible deviations, the shape shall be drawn out and given theshape code 99 and the free dimension shah be indicated in parentheses.The length of straight between two bends shall be at least 4d, see Figure 6.NOTE 1 The length equations for shapes 15,25,26, and 46 are approximate and where the bend angle is greater than 48 the lengthshould be calculated more accurately allowing for the difference between the specified overall dimensions and the true lengthneasured along the central axis of the bar or wire. When the bending angles approach 9 0 º it is preferable to specify shapecode 99 with a fully dimensioned sketch.VOTE 2 For shapes with straight and semicircular lengths (e.g. shape codes 13 and 33) the largest practical radius for the productionof a continuous curve is 200 mm, and for larger radii the curve may be produced by a series of straight sections.

8 © BSI 05-2001