Prime-Line
Prime-Line 9090741 Serrated Flange Bolts 1/4in-20 X 2in Zinc Case
Hex flange bolts with serrated washers resist vibration loosening and meet ASME 18.2.1, 18.6.3 and B1.1 standards
- TypeAutomotive Service & Shop Tools
- ColorTransparent
- Serrated flange bites into surfaces resisting vibration loosening
- Integrated flange washer distributes clamping load over wider area
- Eliminates separate washer under bolt head saving assembly time
- Meets ASME B18.2.1 B18.6.3 B1.1 standards for reliable fit
- Coarse UNC-2A threads suit standard 1/4 inch-20 nuts
Flange Bolts for Vibration-Prone Joints
These 1/4in-20 by 2in serrated flange bolts suit automotive and solar-mounting jobs where vibration loosens standard fasteners. The integrated flange spreads clamping load across a wider area than a separate washer. Serrations under the flange bite into the mating surface to resist back-out. Each piece is zinc plated for corrosion resistance in outdoor or under-hood exposure.
Coarse UNC-2A Thread Class
The single specification that decides fit is the coarse UNC-2A thread class paired with a 1/4in-20 diameter. Matching internal threads must share the same class or the bolt will not engage correctly. ASME B1.1, B18.2.1 and B18.6.3 compliance confirms dimensional control for interchangeable hardware. Verify the nut or tapped hole specification before ordering.
Simple Install With Correct Mating Threads
Installation requires only a standard hex driver or socket once the matching nut or threaded hole is confirmed. No separate washer is needed under the bolt head, reducing parts count. The blunt point starts easily in aligned holes. The common error is using a fine-thread or mismatched-class nut, which prevents full engagement and defeats the serration locking action.
Highlights
- Serrated flange bites into surfaces resisting vibration loosening
- Integrated flange washer distributes clamping load over wider area
- Eliminates separate washer under bolt head saving assembly time
- Meets ASME B18.2.1 B18.6.3 B1.1 standards for reliable fit
- Coarse UNC-2A threads suit standard 1/4 inch-20 nuts
Specifications
| Brand | PRIME-LINE |
|---|---|
| Type | Automotive Service & Shop Tools |
| Color | Transparent |
Questions about this item
How does the 1/4in-20 thread hold up under vibration in a solar rack?
The serrated flange bites into the mounting surface and resists loosening caused by wind or thermal cycling.
Which ASME standards apply to the thread and flange dimensions?
The bolts meet ASME B18.2.1, B18.6.3 and B1.1 for coarse UNC-2A threads and flange geometry.
What clearance does the 2in shank need for a through-bolt installation?
A 1/4in clearance hole and matching nut or threaded hole are required; the flange replaces a separate washer on the bolt side.
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