Metallics JG8NYN164 Nuts 5/16-18 G8 Ny-Ins Locknut St-Yz (Jar 100)

Yes. The JG8NYN164 is a Grade 8 nut, so it matches the proof load class of a Grade 8 (yellow zinc) hex cap screw and won't be the weak link in the joint. Pairing a lower grade nut with a Grade 8 bolt is the usual mistake on high-torque structural and equipment mounting work, and this one avoids it.

No. The JG8NYN164 is not Buy American compliant and is not ARRA compliant, and country of origin is listed as multiple. On a project with domestic sourcing requirements you'll need a domestically produced Grade 8 nylon insert lock nut instead. For private commercial and MRO work the compliance flags don't apply.

It's a hexagonal nylon insert lock nut in 5/16 size, steel with a zinc finish. The nylon collar sits at the top of the nut and deforms around the bolt threads as you run it on, creating friction that keeps the nut from backing off under vibration. No separate lock washer needed. Because the nylon deforms, prevailing torque drops with reuse, so plan on fresh nuts on anything that gets taken apart often.

Width across the hex flats is 0.489 to 0.502 inches, which is a 1/2 inch wrench or socket. Height across the nut body runs 0.329 to 0.359 inches.

The JG8NYN164 is steel with a yellow zinc plating, which gives moderate corrosion resistance for indoor, covered, and light outdoor exposure such as strut and enclosure hardware. For constant wet, coastal, or washdown service, zinc plated Grade 8 steel is not the right call, go to stainless or hot dip galvanized hardware instead. Note also that the nylon insert limits the nut to moderate service temperatures.

Yes. Dimensions conform to ASME B18.16.6 for prevailing torque lock nuts, and threads are to ANSI/ASME B1.1. If your drawing calls out a B18.16.6 nylon insert hex lock nut in 5/16, this answers that callout.

For 5/16 threaded rod, strut hardware, panel and equipment mounting where the joint sees vibration and stays below moderate temperature, a nylon insert nut like this one is the straightforward pick, it locks without a washer and can be run down by hand before torquing. Where heat is a factor, or where you need a nut that can be removed and reinstalled repeatedly without losing grip, use an all metal prevailing torque (distorted thread) lock nut instead. For a nut that has to be fully reusable with no locking feature at all, a plain Grade 8 finished hex nut with a lock washer is the alternative.

They come in a jar of 100 pieces, and 100 count is the order minimum. The jar keeps them sorted on a service van or in a parts crib rather than loose in a bag. Metallics offers other sizes and quantities of this locknut by request.