ASME/ANSI B18.3:1986 Socket Head Cap Hex Socket Screw combines a hex socket drive with a socket head cap profile, making it suitable for fastening points that require reliable clamping, removable maintenance, and standardized assembly. The ASME/ANSI framework suits U.S.-standard projects, export equipment, and cross-regional supply chains, supporting smooth alignment between engineering drawings, purchasing lists, and quality inspection.
From an assembly perspective, the internal hex socket provides deeper tool engagement, enabling higher assembly torque in compact spaces while reducing external head interference. At the same time, the cylindrical head provides useful bearing height and tool engagement depth, supporting high-strength fastening in compact layouts, so the screw can provide stable fastening performance across different sheet thicknesses, appearance requirements, and space limitations.
It is suitable for machinery, molds, automation systems, and joints requiring reliable tightening. Supply configuration can be refined by size range, strength grade, thread specification, recess control, and surface finish, making it suitable for use with washers, nuts, or pre-tapped holes.

unit: mm
|
Nominal diameter d |
ds |
dk |
k |
S |
t |
||||||
|
max |
min |
max |
min |
max |
min |
||||||
|
#0 |
0.0600 |
0.0568 |
0.096 |
0.091 |
0.060 |
0.057 |
0.050 |
0.025 |
|||
|
#1 |
0.0730 |
0.0695 |
0.118 |
0.112 |
0.073 |
0.070 |
0.062 |
0.031 |
|||
|
#2 |
0.0860 |
0.0822 |
0.140 |
0.134 |
0.086 |
0.083 |
0.078 |
0.038 |
|||
|
#3 |
0.0990 |
0.0949 |
0.161 |
0.154 |
0.099 |
0.095 |
0.078 |
0.044 |
|||
|
#4 |
0.1120 |
0.1075 |
0.183 |
0.176 |
0.112 |
0.108 |
0.094 |
0.051 |
|||
|
#5 |
0.1250 |
0.1202 |
0.205 |
0.198 |
0.125 |
0.121 |
0.094 |
0.057 |
|||
|
#6 |
0.1380 |
0.1329 |
0.226 |
0.218 |
0.138 |
0.134 |
0.109 |
0.064 |
|||
|
#8 |
0.1640 |
0.1585 |
0.270 |
0.262 |
0.164 |
0.159 |
0.141 |
0.077 |
|||
|
#10 |
0.1900 |
0.1840 |
0.312 |
0.303 |
0.190 |
0.185 |
0.156 |
0.090 |
|||
|
1/4 |
0.2500 |
0.2435 |
0.375 |
0.365 |
0.250 |
0.244 |
0.188 |
0.120 |
|||
ABOUT US
Better Fastener is a professional fastener enterprise specializing in the manufacturing of steel washers, stainless steel washers, spring washers and sealingwashers. Founded in 2001 as a washer factory, the company expanded into a comprehensive enterprise integrating washers, nuts, bolts, spring nuts and other fastener products in 2010.
The company positions itself as a provider of comprehensive one-stop services for customers, relying on technological R&D, industrial investment and trade distribution.
With an experienced professional team and a sound sales network, Better Fastener has achieved excellent sales performance in both domestic and foreign markets,and has grown into one of the competitive manufacturers and suppliers in China's industrial fastener industry.
Better Fastener is committed to becoming a trusted fastener supplier for customers with reliable product quality, reasonable prices and on-time delivery
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