DIN 6900-1:1990 Hex Head Flat Assembly combines a hex head bolt with a pre-assembled flat washer and is suitable for engineering joints requiring wrench installation, a larger bearing area, and washer supply with the bolt.
The flat washer distributes clamping force and reduces surface damage, while the assembly format reduces pre-installation matching work; the hex head supports higher torque. Compared with ordinary fasteners, this form places more emphasis on controllable installation, surface protection, and efficient management of matching parts for engineering projects requiring stable supply.
It is commonly used in equipment bases, metal brackets, frame structures, vehicle accessories, and field installation projects. According to drawings or service conditions, bolt strength class, washer size, and protective finish can be selected to improve overall fastening performance and service life.

Dimensions unit: inch
|
Nominal diameter d |
M2.5 |
M3 |
(M3.5) |
M4 |
M5 |
M6 |
M8 |
M10 |
M12 |
||
|
a |
0.9 |
1 |
1.2 |
1.4 |
1.6 |
2 |
2.5 |
3 |
3.5 |
||
|
L2 |
Min. |
4 |
4 |
6 |
6 |
6 |
8 |
10 |
12 |
14 |
|
|
h |
DIN 6902 |
Type C |
0.6 |
0.6 |
0.8 |
0.8 |
1 |
1.6 |
2 |
2.5 |
3 |
|
Type A |
0.6 |
0.6 |
0.8 |
0.8 |
1 |
1.6 |
2 |
2.5 |
3 |
||
|
Type B |
0.8 |
0.8 |
0.8 |
1 |
1.6 |
1.6 |
2 |
2.5 |
3 |
||
|
dc |
DIN 6902 |
Type C |
5 |
6 |
7 |
8 |
9 |
11 |
15 |
18 |
20 |
|
Type A |
6 |
7 |
8 |
9 |
10 |
12 |
16 |
20 |
24 |
||
|
Type B |
8 |
9 |
11 |
12 |
15 |
18 |
24 |
30 |
37 |
||
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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