DIN 6921:1983 Hex Head Flange Bolt combines a hex head with an integrated flange bearing surface. It enlarges the contact area without requiring a separate flat washer, making it suitable for joints that need stable clamping and faster assembly.
The flange helps distribute pressure, reduce surface indentation, and provide a degree of improved loosening resistance. Common applications include automotive components, equipment housings, bracket joints, sheet-metal assemblies, and medium-to-light mechanical structures.
Options may include plain flange surfaces or specific anti-slip features, different strength classes, and various surface treatments. In production assembly, flange bolts can reduce part count and improve picking and installation efficiency.

Dimensions unit: mm
| Thread size d | M5 | M6 | M8 | M10 | M12 | M14 | M16 | M20 | ||||
| P | Pitch | Coarse Teeth | 0.8 | 1 | 1.25 | 1.5 | 1.75 | 2 | 2 | 2.5 | ||
| Fine Teeth 1 | / | / | 1 | 1.25 | 1.5 | 1.5 | 1.5 | 1.5 | ||||
| Fine Teeth 2 | / | / | / | 1 | 1.25 | / | / | / | ||||
| b | Reference value | L≤125 | 16 | 18 | 22 | 26 | 30 | 34 | 38 | 46 | ||
| 125<L≤200 | / | / | 28 | 32 | 36 | 40 | 44 | 52 | ||||
| L>200 | / | / | / | / | / | / | 57 | 65 | ||||
| c | Min. | 1 | 1.1 | 1.2 | 1.5 | 1.8 | 2.1 | 2.4 | 3 | |||
| da | Type A | Max. | 5.7 | 6.8 | 9.2 | 11.2 | 13.7 | 15.7 | 17.7 | 22.4 | ||
| Type B | Max. | 6.2 | 7.4 | 10 | 12.6 | 15.2 | 17.7 | 20.7 | 25.7 | |||
| dc | Max. | 11.8 | 14.2 | 18 | 22.3 | 26.6 | 30.5 | 35 | 43 | |||
| ds | Max. | 5 | 6 | 8 | 10 | 12 | 14 | 16 | 20 | |||
| Min. | 4.82 | 5.82 | 7.78 | 9.78 | 11.73 | 13.73 | 15.73 | 19.67 | ||||
| du | Max. | 5.5 | 6.6 | 9 | 11 | 13.5 | 15.5 | 17.5 | 22 | |||
| dw | Min. | 9.8 | 12.2 | 15.8 | 19.6 | 23.8 | 27.6 | 31.9 | 39.9 | |||
| e | Min. | 8.71 | 10.95 | 14.26 | 16.5 | 17.62 | 19.86 | 23.15 | 29.87 | |||
| f | Max. | 1.4 | 2 | 2 | 2 | 3 | 3 | 3 | 4 | |||
| k | Max. | 5.4 | 6.6 | 8.1 | 9.2 | 11.5 | 12.8 | 14.4 | 17.1 | |||
| k1 | Min. | 2 | 2.5 | 3.2 | 3.6 | 4.6 | 5.1 | 5.8 | 6.8 | |||
| r1 | Min. | 0.25 | 0.4 | 0.4 | 0.4 | 0.6 | 0.6 | 0.6 | 0.8 | |||
| r2 | Max. | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.9 | 1 | 1.2 | |||
| r3 | Min. | 0.1 | 0.1 | 0.15 | 0.2 | 0.25 | 0.3 | 0.35 | 0.4 | |||
| r4 | ≈ | 3 | 3.4 | 4.3 | 4.3 | 6.4 | 6.4 | 6.4 | 8.5 | |||
| s | Max.= Nominal | 8 | 10 | 13 | 15 | 16 | 18 | 21 | 27 | |||
| Min. | 7.78 | 9.78 | 12.73 | 14.73 | 15.73 | 17.73 | 20.67 | 26.67 | ||||
| t | Max. | 0.15 | 0.2 | 0.25 | 0.3 | 0.35 | 0.45 | 0.5 | 0.65 | |||
| Min. | 0.05 | 0.05 | 0.1 | 0.15 | 0.15 | 0.2 | 0.25 | 0.3 | ||||
| Thread length b | - | - | - | - | - | - | - | - | ||||
① e min. = 1.12 x s min.
② Material:
a) Steel, strength grade (material): 8.8, 10.9, 12.9, standard DIN ISO 898-1
b) Stainless steel, strength grade (material): A2-70, standard DIN 267-11
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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.
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