Fits and Tolerances

Table: 1 Tolerances for holes of sizes up to 100 mm (H5 to H11)

Diameter steps

in mm

H

5 6 7 8 9 10 11 5-11

over to es ei

0 3 4 6 10 14 25 40 60 0

3 6 5 8 12 18 30 48 75 0

6 10 6 9 15 22 36 48 90 0

10 18 8 11 18 27 43 70 110 0

18 30 9 13 21 33 52 84 130 0

30 50 11 16 25 39 62 100 160 0

50 80 13 19 30 46 74 120 190 0

80 100 15 22 35 54 87 140 220 0

Note :

1. In Table 1 and 2 the tolerances are given in microns (1 micron = 0.001 mm)

2. es = upper deviation and ei = lower deviation

Design against Fluctuating Load

Fig 1: Stress concentration factor (Rectangular

plate with transverse Hole in Tension or

compression)

Fig 2 :Stress concentration factor (Flat plate

with shoulder fillet in Tension or

compression)

Fig 3 : Stress concentration factor

(Round Shaft with shoulder fillet in

Fig 4 : Stress concentration factor

(Round Shaft with shoulder fillet in

Fig 5 : Stress concentration factor

(Round Shaft with shoulder fillet in

Fig 6 : Notch Sensitivity Charts ( for Reversed

Bending and Reversed Axial Stresses)

Fig 7 : Notch Sensitivity Charts ( for Reversed

torsional shear Stresses)

Diameter (d) (mm) Kb

d ≤ 7.5 1

7.5 < d ≤ 50 0.85

d > 50 0.75

Reliability R (%) Kc

50 1

90 0.897

95 0.868

99 0.814

99.9 0.753

99.99 0.702

99.999 0.659

Fig 8 : Surface Finish

Table 3 : Values of Size Factor Table 4 : Reliability Factor

Nominal diameter, d

(mm) Pitch, p (mm)

22, 24, 26, 28 5

30, 32, 36 6

40, 44 7

48, 50, 52 8

55, 60 9

65, 70, 75, 80 10

80, 90, 95, 100 12

Designation

Nominal

or

major

Dia. d/D

(mm)

Pitch

(p) mm

Pitch

diameter

dp/Dp

(mm)

Minor

Dia. Dc Minor

Dia. Dc

(mm)

Tensile

Stress

Area

M4 4 0.7 3.545 3.141 3.242 8.78

M5 5 0.8 4.48 4.019 4.134 14.2

M6 6 1 5.35 4.773 4.917 20.1

M8 8 1.25 7.188 6.466 6.647 36.6

M10 10 1.5 9.026 8.16 8.376 58

M12 12 1.75 10.863 9.853 10.106 84.3

M16 16 2 14.701 13.546 13.835 157

M20 20 2.5 18.376 16.933 17.294 245

M24 24 3 22.051 20.319 20.752 353

M30 30 3.5 27.727 25.706 26.211 561

M36 36 4 33.402 31.093 31.67 817

M42 42 4.5 39.077 36.479 37.129 1120

M48 48 5 44.752 41.866 42.587 1470

M56 56 5.5 52.428 49.252 50.046 2030

M64 64 6 60.103 56.639 57.505 2680

M72 72 6 68.103 64.639 65.505 3460

M80 80 6 76.103 72.639 73.505 4340

M90 90 6 86.103 82.639 83.505 5590

M100 100 6 96.103 92.639 93.505 7000

Nominal diameter, d (mm) Pitch, p (mm)

24, 28 5

32, 36 6

40, 44 7

48, 52 8

60 9

70, 80 10

90, 100 12

Table 5 : Proportion of square threads

(normal series)

Table 6 : Proportion of ISO metric trapezoidal

threads

Table 7 : Basic dimensions for ISO metric screw threads (coarse series)

Designation

Nominal

or major

dia d/D

(mm)

Pitch

(p)

(mm)

Pitch

diameter

dp/Dp

(mm)

Minor

diameter

dc (mm)

Minor

diameter

Dc (mm)

Tensile

stress

area

(mm2)

M 6 x 1 6 1 5.35 4.773 4.917 20.1

M 6 x 0.75 6 0.75 5.513 5.08 5.188 22

M 8 x 1.25 8 1.25 7.188 6.466 6.647 36.6

M 8 x 1 8 1 7.35 6.773 6.917 39.2

M 10 x 1.25 10 1.25 9.188 8.466 8.647 61.2

M 10 x 1 10 1 9.35 8.773 8.917 64.5

M 12 x 1.5 12 1.5 11.026 10.16 10.376 88.1

M 12 x 1.25 12 1.25 11.188 10.466 10.647 92.1

M 16 x 1.5 16 1.5 15.026 14.16 14.376 167

M 16 x 1 16 1 15.35 14.773 14.917 178

M 20 x 2 20 2 18.701 17.546 17.835 258

M 20 x 1.5 20 1.5 19.026 18.16 18.376 272

M 24 x 2 24 2 22.701 21.546 21.835 384

M 24 x 1.5 24 1.5 23.026 22.16 22.376 401

M 30 x 3 30 3 28.051 26.319 26.752 581

M 30 x 2 30 2 28.701 27.546 27.835 621

M 36 x 3 36 3 34.051 32.319 32.752 865

M 36 x 2 36 2 34.701 33.546 33.835 915

M 42 x 4 42 4 39.402 37.093 37.67 1150

M 42 x 3 42 3 40.051 38.319 38.752 1210

M 48 x 4 48 4 45.402 43.093 43.67 1540

M 48 x 3 48 3 46.051 44.319 44.752 1600

Table 8 : Basic dimensions for ISO metric screw threads (fine series)

Shaft keys and couplings

Diameters (mm)

5 20 45 90

6 22 50 100

8 25 55 110

10 28 60 120

12 30 65 140

14 32 70 160

16 35 75 180

18 40 80 200

Shaft diameter Key Size Keyway

depth

Above Up to and

including b x h

6 8 2 x 2 1.2

8 10 3 x3 1.8

10 12 4 x 4 2.5

12 17 5 x 5 3

17 22 6 x 6 3.5

22 30 8 x 7 4

30 38 10 x 8 5

38 44 12 x 8 5

44 50 14 x 9 5.5

50 58 16 x 10 6

58 65 18 x 11 7

65 75 20 x 12 7.5

75 85 22 x 14 9

85 95 25 x 14 9

95 110 28 x 16 10

110 130 32 x 18 11

130 150 36 x 20 12

150 170 40 x 22 13

170 200 45 x 25 15

200 230 50 x 28 17

Application Kb Kt

Load gradually applied 1.5 1

Load suddenly applied

(minor shock) 1.5 - 2.0 1.0 - 1.5

Load suddenly applied

(heavy shock) 2.0 - 3.0 1.5 - 3.0

Table 9 : Standard diameters of steelbars

used for structural and general engineering

purposes

Table 11 : Dimensions of square and rectangular sunk key (in mm)

Table 10 : Values of shock and fatigue

factor Kb and Kt