Related Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
ASME B18.3 Hexagon Socket Head Shoulder Screws – Dimensions, Specifications & Standards
Socket Head Shoulder Screws for Pivoting & Bearing Functions.
ASME B18.3 Hexagon Socket Head Shoulder Screws — also known as shoulder bolts or stripper bolts — are precision inch-series fasteners with a smooth, accurately ground cylindrical shoulder between the head and threaded section, serving as a bearing surface, pivot, guide pin, or shaft in mechanical assemblies such as stamping dies, linkages, and automated machinery. The standard governs shoulder diameter and length tolerances, head diameter, head height, hexagonal socket size, thread diameter, thread length, and key engagement depth. In critical applications, these screws comply with ASTM A1014/A1014M for UNS N07718 (Inconel 718) material, providing high tensile strength and corrosion resistance for high-temperature service. Alloy steel versions per ASTM A574 ensure a minimum 180,000 PSI tensile strength. The shoulder diameter is held to tighter tolerances than the thread, making it the functional reference surface in precision designs.
ASME B18.3 Hexagon Socket Head Shoulder Screws Dimensions (mm)
| Nominal Size (Basic Shoulder Diameter) | Shoulder Diameter, D | Head Diameter, A | Head Height, H | Chamfer or Radius, C | Nominal Hexagon Socket Size, J | Key Engagement, T | Fillet Transition Diameter, M | Head Fillet Radius, R | Shoulder Neck Diameter, K | Shoulder Neck Width, F | Nominal Thread Diameter, D1 | Threads, in. | Thread Neck Diameter, G | Thread Neck Width, I | Thread Neck Fillet, N | Basic Thread Length, E | Chamfer or Radius, P | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Max. | Min. | Max. | Min. | Max. | Min. | Max. | Basic | Decimal | Min. | Max. | Min. | Min. | Max. | Max. | Min. | Max. | Max. | Min. | Max. | |||||
| 1/8 | 0.1250 | 3.124 | 3.073 | 6.350 | 5.969 | 3.175 | 2.921 | 0.203 | 5/64 | 1.981 | 1.702 | 3.505 | 0.152 | 2.743 | 1.016 | 4 (0.1120) | 40 | 1.930 | 1.753 | 1.981 | 0.406 | 0.254 | 3.988 | 0.203 |
| 5/32 | 0.1560 | 3.912 | 3.861 | 7.137 | 6.756 | 3.175 | 2.921 | 0.203 | 3/32 | 2.388 | 1.702 | 4.369 | 0.178 | 3.556 | 1.016 | 6 (0.1380) | 32 | 2.540 | 2.362 | 1.600 | 0.457 | 0.305 | 4.750 | 0.203 |
| 3/16 | 0.1875 | 4.699 | 4.648 | 7.925 | 7.518 | 3.962 | 3.708 | 0.305 | 3/32 | 2.388 | 2.007 | 5.258 | 0.203 | 3.912 | 1.016 | 8 (0.1640) | 32 | 3.048 | 2.845 | 1.753 | 0.457 | 0.305 | 4.801 | 0.203 |
| 1/4 | 0.2500 | 6.299 | 6.248 | 9.525 | 9.068 | 4.775 | 4.496 | 0.508 | 1/8 | 3.175 | 2.388 | 7.010 | 0.229 | 5.766 | 2.362 | 10 (0.1900) | 24 | 3.607 | 3.378 | 2.108 | 0.584 | 0.432 | 9.525 | 0.254 |
| 5/16 | 0.3125 | 7.887 | 7.836 | 11.125 | 10.643 | 5.563 | 5.309 | 0.660 | 5/32 | 3.962 | 2.972 | 8.763 | 0.305 | 7.341 | 2.362 | 1/4 (0.2500) | 20 | 4.902 | 4.623 | 2.540 | 0.711 | 0.559 | 11.125 | 0.254 |
| 3/8 | 0.3750 | 9.474 | 9.423 | 14.275 | 13.792 | 6.350 | 6.096 | 0.787 | 3/16 | 4.775 | 3.581 | 10.490 | 0.381 | 8.941 | 2.362 | 5/16 (0.3125) | 18 | 6.325 | 6.020 | 2.819 | 0.787 | 0.635 | 12.700 | 0.254 |
| 1/2 | 0.5000 | 12.649 | 12.598 | 19.050 | 18.517 | 7.925 | 7.671 | 1.016 | 1/4 | 6.350 | 4.775 | 13.970 | 0.508 | 12.116 | 2.362 | 3/8 (0.3750) | 16 | 7.722 | 7.391 | 3.175 | 0.889 | 0.737 | 15.875 | 0.254 |
| 5/8 | 0.6250 | 15.824 | 15.773 | 22.225 | 21.666 | 9.525 | 9.271 | 1.270 | 5/16 | 7.925 | 5.944 | 17.450 | 0.610 | 15.291 | 2.362 | 1/2 (0.5000) | 13 | 10.516 | 10.084 | 3.912 | 1.067 | 0.914 | 19.050 | 0.381 |
| 3/4 | 0.7500 | 19.000 | 18.948 | 25.400 | 24.816 | 12.700 | 12.446 | 1.753 | 3/8 | 9.525 | 7.137 | 20.980 | 0.762 | 18.466 | 2.362 | 5/8 (0.6250) | 11 | 13.233 | 12.751 | 4.623 | 1.295 | 1.143 | 22.225 | 0.381 |
| 1 | 1.0000 | 25.349 | 25.298 | 33.325 | 32.690 | 15.875 | 15.494 | 2.108 | 1/2 | 12.700 | 9.525 | 27.889 | 1.016 | 24.816 | 3.175 | 3/4 (0.7500) | 10 | 16.205 | 15.646 | 5.080 | 1.397 | 1.245 | 25.400 | 0.508 |
| 1 1/4 | 1.2500 | 31.700 | 31.648 | 44.450 | 43.764 | 19.050 | 18.669 | 2.591 | 5/8 | 15.875 | 11.913 | 34.747 | 1.270 | 31.166 | 3.175 | 7/8 (0.8750) | 9 | 19.050 | 18.440 | 5.639 | 1.575 | 1.422 | 28.575 | 0.508 |
| 1 1/2 | 1.5000 | 38.049 | 37.998 | 53.975 | 53.213 | 25.400 | 24.892 | 3.505 | 7/8 | 22.225 | 16.662 | 41.605 | 1.524 | 37.541 | 3.175 | 1 1/8 (1.1250) | 7 | 24.486 | 23.724 | 7.264 | 1.829 | 1.676 | 38.100 | 0.508 |
| 1 3/4 | 1.7500 | 44.399 | 44.348 | 60.325 | 59.563 | 28.575 | 28.067 | 3.988 | 1 | 25.400 | 19.050 | 48.463 | 1.778 | 43.891 | 3.175 | 1 1/4 (1.2500) | 7 | 27.661 | 26.899 | 7.264 | 1.829 | 1.676 | 44.450 | 0.508 |
| 2 | 2.0000 | 50.749 | 50.698 | 69.850 | 69.088 | 31.750 | 31.242 | 4.470 | 1 1/4 | 31.750 | 23.800 | 55.321 | 2.032 | 50.241 | 3.175 | 1 1/2 (1.5000) | 6 | 33.198 | 32.436 | 8.458 | 2.591 | 2.438 | 50.800 | 0.508 |
ASME B18.3 Hexagon Socket Head Shoulder Screws Length Tolerances(mm)
| Nominal Length | Nominal Size, Tolerances on Lengths | |||
|---|---|---|---|---|
| 0 Through 3/8, Incl. |
7/16 Through 3/4, Incl. |
7/8 Through 1 1/2, Incl. |
Over 1 1/2 | |
| Up to 25.4, incl. | -0.762 | -0.762 | -1.270 | ... |
| Over 25.4 to 63.5, incl. | -1.016 | -1.524 | -2.540 | -4.572 |
| Over 63.5 to 152.4, incl. | -1.524 | -2.032 | -3.556 | -5.080 |
| Over 152.4 | -3.048 | -3.048 | -5.080 | -6.096 |
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