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ASME B18.31.1M Metric Clamping Full Body Type Studs
Metric clamping studs with a full body shank and precision threads on both ends, engineered for reliable clamping force in flanged and pressure vessel assemblies.
ASME B18.31.1M Metric Clamping Full Body Type Studs are a specific configuration within the B18.31.1M metric stud family, designed to develop and maintain precise clamping force across bolted joint interfaces in flanges, pressure vessels, heat exchangers, and structural assemblies. Unlike conventional double-end studs, clamping full body type studs maintain a consistent full-body nominal diameter throughout the unthreaded shank length, ensuring that the stud acts as a rigid, non-yielding clamping element between the two mating surfaces without localized stress concentration along the body. Dimensioned entirely in metric units and compliant with ISO and DIN interchangeability requirements, these studs are essential for internationally sourced equipment and global engineering projects where metric standards govern the design. The ASME B18.31.1M standard precisely defines thread lengths, shank tolerances, and overall dimensions in millimeters, ensuring reliable engagement with metric heavy hex nuts and washers while delivering the uniform clamping load distribution required by pressure equipment design codes.
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 |
Frequently Asked Questions
- What does ASME B18.31.1M metric clamping full-body studs cover?
- ASME B18.31.1M is the metric dimensional standard for metric clamping full-body studs. It defines head dimensions, body diameter, thread length, total length, drive recess, and tolerances so any compliant metric clamping full-body studs interchanges with standard nuts, washers and wrenches across manufacturers.
- What size range is available for metric clamping full-body studs under ASME B18.31.1M?
- metric clamping full-body studs under ASME B18.31.1M covers M6 to M64 nominal diameter, full unthreaded body with both ends threaded. TorqBolt manufactures the full range in ASTM A193 Grades B7, B7M, B8, B8M and the full ASTM A320 cryogenic counterpart on customer specification.
- What is the metric/inch counterpart of ASME B18.31.1M metric clamping full-body studs?
- The companion specification for metric clamping full-body studs is ASME B18.31.1 inch clamping studs. Both standards share equivalent functional dimensions but use the corresponding measurement system (inch vs metric ISO M-series).
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