5/16"-18 Locknuts | McMaster-Carr

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System of Measurement

Nut Type

Tamper Resistant

With Sight Hole

Material

Grade 5 Titanium

Stainless Steel

Locking Type

Distorted Thread

Finish

Black Zinc Plated

Corrosion-Resistant Coated

Phosphate Coated

Zinc Flake Coated

Zinc Yellow-Chromate Plated

Fastener Strength Grade/Class

Width

Hex Nut Profile

Height

Thread Type

Performance

Corrosion Resistant

Vibration Resistant

Thread Spacing

Thread Direction

Fastener Strength Rating

Flange Diameter

Washer Material

400 Series Stainless Steel

Thread Fit

Unified Standard Class 2B

Unified Standard Class 3B

Color

Drive Style

Distorted Thread Type

DFARS Specialty Metals

RoHS

Military Specification

REACH

Export Control Classification Number (ECCN)

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94 Products

Locknuts

Nylon-Insert Locking About Nylon-Insert Locking

About Nylon-Insert Locking

Nylon-Insert Locknuts

Nylon-Insert Locknuts

Versatile and economical—the most commonly used locknuts

Thin-Profile Nylon-Insert Locknuts

About half the height of standard nuts to fit in spaces with low clearance

Heavy-Profile Nylon-Insert Locknuts

About 10% wider and taller than standard nuts to handle heavier loads

Thin-Heavy-Profile Nylon-Insert Locknuts

Fit in low-clearance spaces and handle heavier loads than standard nuts

Mil. Spec. Nylon-Insert Locknuts

Mil. Spec. Nylon-Insert Locknuts

Meet strict U.S. military standards for material and construction

Distorted-Thread Locking About Distorted-Thread Locking

About Distorted-Thread Locking

Top-Lock Distorted-Thread Locknuts

Top-Lock Distorted-Thread Locknuts

Irregularly shaped threads at the top grip screws tighter than a nylon insert

Center-Lock Distorted-Thread Locknuts

Center-Lock Distorted-Thread Locknuts

Thread on from either side so there’s no risk of damaging screws

Left-Hand-Thread Center-Lock Distorted-Thread Locknuts

Left-Hand-Thread Center-Lock Distorted-Thread Locknuts

Secure parts that rotate counterclockwise, such as the propeller on a mixer

Lock Washer About Lock Washer

About Lock Washer

Locknuts with External-Tooth Lock Washer

Locknuts with External-Tooth Lock Washer

Twist into place by hand to save on assembly time

Cotter-Pin Lockable About Cotter-Pin Lockable

About Cotter-Pin Lockable

Locknuts for use with Cotter Pins

Locknuts for use with Cotter Pins

Secure rotating parts subjected to mild vibration, such as wheels on carts

Flex-Top Locking About Flex-Top Locking

About Flex-Top Locking

Flex-Top Locknuts for Heavy Vibration

Flex-Top Locknuts for Heavy Vibration

Stronger hold than nylon-insert and distorted-thread locknuts

Thin-Profile Flex-Top Locknuts for Heavy Vibration

About two-thirds the height of standard nuts to fit in spaces with low clearance

Heavy-Profile Flex-Top Locknuts for Heavy Vibration

About 10% wider and taller than standard nuts to handle heavier loads

Thin-Heavy-Profile Flex-Top Locknuts for Heavy Vibration

Fit in low-clearance spaces and handle heavier loads than standard nuts

Serration Locking About Serration Locking

About Serration Locking

Serrated Locknuts

Serrated Locknuts

Easiest to install but least effective against vibration

Other Products

Flange Nuts

The flange distributes pressure, so you don't need a washer

Cap Nuts

Cover and protect threads while adding a finished look; also known as acorn nuts

Easy to tighten and loosen by hand for making frequent adjustments

Tamper-Resistant Nuts

Tamper-Resistant Nuts

Hard to detach without special tools to prevent unwanted removal

The quick brown fox jumped over the lazy dog. Pedestal (35" Ht. x 4" Wd. x 4" Dp.)