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    ASME B18.31.1M Metric Clamping Full Body Type Studs – Dimensions, Specifications & Standards

    Metric Clamping Full Body Studs for High-Integrity Bolted Joints.

    ASME B18.31.1M Metric Clamping Full Body Type Studs are metric-series unheaded fasteners with threads on both ends and a full-diameter unthreaded body shank, providing excellent clamping performance in bolted flange joints, pressure vessel assemblies, and structural connections. The standard defines metric dimensions for body diameter, overall length, thread length on each end, thread pitch, and body diameter tolerances. These studs are used per ASTM A1014/A1014M for UNS N07718 (Inconel 718) bolting with exceptional tensile strength, fatigue resistance, and corrosion resistance for offshore, LNG, and high-temperature chemical processing. The metric counterpart to ASME B18.31.2 inch-series clamping studs, the full-body design ensures uniform stress distribution, minimizing galling or fatigue failure under cyclic loading.

    ASME B18.31.1M Metric Clamping Full Body Type Studs Dimensions Drawing

    ASME B18.31.1M Metric Clamping Full Body Type Studs Dimensions (mm)

    Nominal Size
    Diameter, D
    Thread Length, B UMax.
    = 2P
    Nominal Length, L Body Diameter, DS
    LT ≤ 250 250 < LT ≤ 400 LT > 400 Max. Min. (by Length)
    Min. Max. Min. Max. Min. Max. Range Incr. LT ≤ 150 LT > 150
    M1.6 9.2 9.9 - - - - 0.7 25-50 5 1.60 1.29 1.29
    M2 10 10.8 - - - - 0.8 25-50 5 2.00 1.65 1.65
    M2.5 11 11.9 - - - - 0.9 30-50 5 2.50 2.12 2.12
    M3 12 13 - - - - 1 30-50 5 3.00 2.58 2.58
    M4 14 15.4 - - - - 1.4 35-90 5 4.00 3.43 3.43
    M5 16 17.6 - - - - 1.6 40-90 5 5.00 4.36 4.36
    M6 18 20 24 26 - - 2 50-90
    100-160
    5
    10
    6.00 5.82 5.70
    M8 18 20.5 26.5 24 - - 2.5 50-90
    ≥ 100
    5
    10
    8.00 7.78 7.64
    M10 26 29 32 35 45 48 3 60-160
    ≥ 180
    10
    20
    10.00 9.78 9.64
    M12 30 33.5 36 39.5 49 52.5 3.5 60-160
    ≥ 180
    10
    20
    12.00 11.73 11.57
    M14 34 38 40 44 53 57 4 80-160
    ≥ 180
    10
    20
    14.00 13.73 13.57
    M16 38 42 44 48 57 61 4 90-160
    ≥ 180
    10
    20
    16.00 15.73 15.57
    M20 46 51 52 57 65 70 5 100-160
    > 180
    10
    20
    20.00 19.67 19.48
    M24 54 60 60 66 73 79 6 130-160
    ≥ 180
    10
    20
    24.00 23.67 23.48
    M30 66 73 72 79 85 92 7 150-160
    ≥ 180
    10
    20
    30.00 - 29.48
    M36 78 86 84 92 97 105 8 ≥ 200 20 36.00 - 35.38
    M42 90 99 96 105 109 118 9 ≥ 240 20 42.00 - 41.38
    M48 - - 108 118 121 131 10 ≥ 280 20 48.00 - 47.38
    M56 - - 124 135 137 148 11 ≥ 300 20 56.00 - 55.26
    M64 - - 140 152 153 165 12 ≥ 340 20 64.00 - 63.26
    M72 - - 156 168 169 181 12 ≥ 380 20 72.00 - 71.26
    M80 - - 172 184 185 197 12 ≥ 400 20 80.00 - 79.26
    M90 - - - - 205 217 12 ≥ 440 20 90.00 - 89.13
    M100 - - - - 225 237 12 ≥ 480 20 100.00 - 99.13

    ASME B18.31.1M Metric Full Body Clamping Type Studs Length Tolerances (mm)

    Nominal Length Tolerance
    Over Through
    6 10 ± 0.29
    10 18 ± 0.35
    18 30 ± 0.42
    30 50 ± 0.50
    50 80 ± 0.95
    80 120 ± 1.10
    120 180 ± 1.25
    180 250 ± 1.45
    250 315 ± 1.60
    315 400 ± 1.80
    400 500 ± 2.00
    >500 ... ± 5.00