ASME B18.6.3 (H9B-VI):2024 Hex Head Heavy Hex Torx Screw combines an external hex head with an internal Torx recess, allowing both wrench-driven and internal-drive installation methods where assembly or maintenance conditions vary.
The recessed drive provides positive tool location, while the heavy hex head helps enlarge the contact area and improve handling during tightening. This makes the screw useful in applications that require installation efficiency, serviceability, and robust head geometry.
It is suitable for equipment housings, bracket joints, engineering assemblies, vehicle components, and industrial maintenance work. Different materials, coatings, and dimensional options can be selected to improve fastening reliability in outdoor, humid, or vibration-prone environments.

Dimensions unit: inch
|
Thread size d |
4# |
5# |
6# |
8# |
10# |
12# |
1/4 |
5/16 |
3/8 |
||
|
d |
Nominal |
0.112 |
0.125 |
0.138 |
0.164 |
0.19 |
0.216 |
0.25 |
0.3125 |
0.375 |
|
|
PP |
40 |
40 |
32 |
32 |
24 |
24 |
20 |
18 |
16 |
||
|
M |
Reference value |
0.111 |
0.111 |
0.132 |
0.155 |
0.178 |
0.2 |
0.221 |
0.266 |
0.312 |
|
|
Slot number |
T10 |
T10 |
T15 |
T20 |
T25 |
T27 |
T30 |
T40 |
T45 |
||
|
P |
Max. |
0.04 |
0.05 |
0.051 |
0.065 |
0.08 |
0.08 |
0.095 |
0.125 |
0.155 |
|
|
Min. |
0.035 |
0.04 |
0.04 |
0.05 |
0.065 |
0.065 |
0.08 |
0.1 |
0.125 |
||
|
s1 |
Standard type |
Max. |
0.188 |
0.188 |
0.25 |
0.25 |
0.312 |
0.312 |
0.375 |
0.5 |
0.562 |
|
Min. |
0.181 |
0.181 |
0.244 |
0.244 |
0.305 |
0.305 |
0.367 |
0.489 |
0.551 |
||
|
s2 |
Big hexagon |
Max. |
0.219 |
0.25 |
/ |
0.312 |
/ |
0.375 |
0.438 |
/ |
/ |
|
Min. |
0.213 |
0.244 |
/ |
0.305 |
/ |
0.367 |
0.428 |
/ |
/ |
||
|
e1 |
Standard type |
Min. |
0.202 |
0.202 |
0.272 |
0.272 |
0.34 |
0.34 |
0.409 |
0.545 |
0.614 |
|
e2 |
Big hexagon |
Min. |
0.238 |
0.272 |
/ |
0.34 |
/ |
0.409 |
0.477 |
/ |
/ |
|
k |
Max. |
0.06 |
0.07 |
0.093 |
0.11 |
0.12 |
0.155 |
0.19 |
0.23 |
0.295 |
|
|
Min. |
0.049 |
0.058 |
0.08 |
0.096 |
0.105 |
0.139 |
0.172 |
0.208 |
0.27 |
||
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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