Keps K Lock Nuts in Zinc Plated Steel

Hex Nuts with an Attached Free-Spinning Washer

A Keps K-lock nut is a nut with an attached or captive, free-spinning washer. They may also be referred to as Keps Nuts, k-lock nuts, star nuts, or captive lock washer nuts. They are used to make an assembly more convenient as they combine both a hex nut and a lock washer into a single fastener.

K Lock Nuts Feature a conical external tooth washer attached to the bottom of the nut. This integrated lock washer bites into the surface material, providing increased breakaway torque and decreased likelihood of the nut loosening.

Zinc Plated Steel

Zinc is by far the most common and economical type of plating for fasteners. The zinc plating adds a protective "sacrificial" top layer against corrosion while also adding a shiny finish to the fastener. Zinc plating is ideal for indoor use where it won't be constantly exposed to harsh elements.

Nut Size
Width Across Flats Overall Thickness Washer Diameter
#4
1/4" Max 0.098 - Min 0.087
Max 0.286 - Min 0.277
#5 5/16" Max 0.114 - Min 0.102 Max 0.348 - Min 0.338
#6
5/16" Max 0.114 - Min 0.102 Max 0.348 - Min 0.338
#8
11/32" Max 0.130 - Min 0.117 Max 0.381 - Min 0.370
#10
3/8" Max 0.130 - Min 0.117 Max 0.406 - Min 0.395
#12 7/16" Max 0.161 - Min 0.148 Max 0.506 - Min 0.494
1/4" 7/16" Max 0.193 - Min 0.178 Max 0.506 - Min 0.494
5/16" 1/2" Max 0.273 - Min 0.258 Max 0.592 - Min 0.579
3/8" 9/16" Max 0.385 - Min 0.365 Max 0.665 - Min 0.651

FAQs

How do K nuts work?

Keps K lock nuts are standard hex nuts with a free-spinning captive serrated washer attached. This washer bites into the surface material to help the nut resist vibration. Keps nuts effectively combine hex nuts with external tooth lock washers into a single fastener for ease of use.

What is the main difference between a KEPS nut and a Nylock nut?

Keps nuts use a serrated captive washer that's attached to the nut to bite into the surface material to create tension and resist vibration. Nylock nuts use a nylon insert that the screw will cut threads into, creating friction between the screw threads and the nylon to prevent loosening. Both are lock nuts, but their methods of locking are their main difference.

What are locking nuts for?

Lock nuts are an easy to use, cost-effective solution to protecting against vibration-related loosening. They're used to protect applications from loosening over time.

What is zinc plated steel?

Zinc plated steel is steel that goes through the process of adding a layer or coating of zinc to protect the steel from corrosion. The added layer of zinc sacrifices itself to keep the steel from rusting, even if the plating is damaged.

Is zinc plated steel rust proof?

No. Zinc plating adds a layer of corrosion resistance for rust protection. Still, it's a thin plating, and it's not as rust resistant as hot-dip galvanizing, which also uses a zinc top layer. While not the most corrosive resistant of materials, zinc plating is easily the most economical and commonly used.

Can zinc plated steel be used outside?

Zinc plating is not a good form of corrosive protection for outdoor use, especially near saltwater or in marine environments. For those applications, stainless steel or potentially hot-dip galvanized steel would work better. Zinc-plated steel is better for indoor use.