ASME/ANSI B18.6.3:2010 Oval Fillister Head Square Drive Screw combines a square drive with a oval fillister head, 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 square recess gives positive tool engagement and strong location, helping reduce slip-out risk and improve repeatable assembly. At the same time, combines a cylindrical head with a rounded top, retaining deeper recess space while offering a smoother exposed profile, so the screw can provide stable fastening performance across different sheet thicknesses, appearance requirements, and space limitations.
It suits instrument components, precision equipment housings, and applications balancing driving stability with appearance. It can be supplied in carbon steel, alloy steel, stainless steel, and other materials, with zinc plating, nickel plating, black oxide, phosphating, or other finishes to balance corrosion resistance, appearance, and assembly friction.

Unit: inch
|
Thread size d |
dk |
k |
h |
s |
t |
|||||
|
max |
min |
max |
min |
max |
min |
max |
min | |||
|
#3 |
0.161 |
0.145 |
0.07 |
0.061 |
0.095 |
0.077 |
0.07 |
0.038 |
0.028 |
|
|
#4 |
0.183 |
0.166 |
0.079 |
0.069 |
0.107 |
0.088 |
0.07 |
0.038 |
0.028 |
|
|
#5 |
0.205 |
0.187 |
0.088 |
0.078 |
0.12 |
0.1 |
0.091 |
0.065 |
0.05 |
|
|
#6 |
0.226 |
0.208 |
0.096 |
0.086 |
0.132 |
0.111 |
0.091 |
0.065 |
0.05 |
|
|
#8 |
0.27 |
0.25 |
0.113 |
0.102 |
0.156 |
0.133 |
0.112 |
0.075 |
0.06 |
|
|
#10 |
0.313 |
0.292 |
0.13 |
0.118 |
0.18 |
0.156 |
0.112 |
0.075 |
0.06 |
|
|
#12 |
0.357 |
0.334 |
0.148 |
0.134 |
0.205 |
0.178 |
0.133 |
0.095 |
0.08 |
|
|
1/4 |
0.414 |
0.389 |
0.17 |
0.155 |
0.237 |
0.207 |
0.133 |
0.095 |
0.08 |
|
|
5/16 |
0.518 |
0.49 |
0.211 |
0.194 |
0.295 |
0.262 |
0.191 |
0.1 |
0.085 |
|
|
3/8 |
0.622 |
0.59 |
0.253 |
0.233 |
0.355 |
0.315 |
0.191 |
0.1 |
0.085 |
|
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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