ASME/ANSI B18.5 (T5):2008 Round Head Double Nib Bolt has two nibs below the round head, offering stronger anti-rotation support than a single-nib style. It is suitable for plate or wood connections requiring higher installation stability.
The double nibs share seating force and restrict head rotation during tightening. Typical uses include guardrails, vehicle accessories, wooden platforms, temporary works, and assemblies that need one-side operation. The smooth round head also supports safety and appearance.
Nib spacing, base material strength, slot form, and grip thickness should be confirmed before use. For outdoor or long-term loaded structures, corrosion-resistant coatings and suitable washers can improve overall joint life.

Dimensions unit: mm
| Nominal diameter d | #10 | 1/4 | 5/16 | 3/8 | 7/16 | 1/2 | |
| ds | max | 0.199 | 0.26 | 0.324 | 0.388 | 0.452 | 0.515 |
| ds | min | 0.182 | 0.237 | 0.298 | 0.36 | 0.421 | 0.483 |
| dk | max | 0.469 | 0.594 | 0.719 | 0.844 | 0.969 | 1.094 |
| dk | min | 0.438 | 0.563 | 0.688 | 0.782 | 0.907 | 1.032 |
| k | max | 0.114 | 0.145 | 0.176 | 0.208 | 0.239 | 0.270 |
| k | min | 0.094 | 0.125 | 0.156 | 0.188 | 0.219 | 0.250 |
| n | max | 0.098 | 0.114 | 0.145 | 0.161 | 0.192 | 0.208 |
| n | min | 0.078 | 0.094 | 0.125 | 0.141 | 0.172 | 0.188 |
| n1 | max | 0.395 | 0.458 | 0.551 | 0.645 | 0.739 | 0.833 |
| n1 | min | 0.375 | 0.438 | 0.531 | 0.625 | 0.719 | 0.813 |
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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