Prime-Line 9090646 Serrated Flange Bolt 1/4in-20 x 3/4in Zinc Case Hard

Prime-Line 9090646 Serrated Flange Bolt

The Prime-Line 9090646 is a zinc-plated, case-hardened serrated flange bolt with a 1/4in-20 coarse thread and 3/4in length. It meets ASME B18.2.1, ASME B18.6.3 and ASME B1.1 specifications for dimensional and thread quality. The integrated flange removes the need for a separate washer under the bolt head. This fastener suits maintenance crews and assembly lines that require vibration-resistant clamping.

Build integration and vibration resistance

The serrations under the flange bite into the mating surface to resist loosening from vibration, reducing the chance of joint failure over time. A nut or threaded hole of matching diameter and thread class is required to complete the joint; a standard washer is still needed on the nut side unless a flange nut is used. The blunt point style allows straightforward engagement in through-holes or tapped holes without specialised tooling. This one-piece design streamlines inventory by replacing a bolt-and-washer combination with a single component.

Upgrade from standard hex bolts

Switching from a plain hex bolt and flat washer to this flange bolt removes a component from the bill of materials and cuts assembly time per joint. The serrated flange provides a mechanical lock that a smooth washer cannot, making the jump worthwhile where vibration or thermal cycling cause conventional hardware to back out. Buyers who need a prevailing-torque locknut or adhesive threadlocker instead of a serrated flange should evaluate those alternatives separately.