Black-Oxide Low-Strength Steel Locknuts
with Spring-Lock Washer, 4-40 Thread Size
Thread Direction | Right Hand |
Hex Nut Profile | Standard |
Locking Type | Lock Washer |
Lock Washer Type | Spring |
Fastener Strength Rating | Low |
Finished Material | Black-Oxide Steel |
Thread Size | 4-40 |
Width | 1/4" |
Height | 9/64" |
Washer | |
OD | 0.328" |
Material | Steel |
Drive Style | External Hex |
Nut Type | Hex, Locknut |
Performance | Vibration Resistant |
System of Measurement | Inch |
Thread Fit | Unified Standard Class 2B |
Thread Spacing | Coarse |
Thread Type | UNC |
Country of Origin | Taiwan |
DFARS Compliance | Specialty Metals COTS-Exempt |
Export Control Classification Number (ECCN) | EAR99 |
REACH Compliance | REACH (EC 1907/2006) (01/21/2025, 247 SVHC) Compliant |
RoHS Compliance | RoHS 3 (2015/863/EU) Compliant |
Schedule B Number | 731816.0000 |
U.S.–Mexico–Canada Agreement (USMCA) Qualifying | No |
The curved, spring-like washer grips surfaces more tightly than tooth-lock washers for better vibration resistance. These locknuts also install just as quickly since you can twist them into place by hand. Once the nut is against your material, tighten it down with a wrench or socket. The washer's smooth edges won't mar the surface like teeth can. As long as the washer stays intact, you can reuse these locknuts.
Low-Strength Steel—Rated Grade 2, Class 6, or lower, these locknuts are about half as strong as medium-strength steel nuts. Use them with screws that have a similar strength rating to avoid stripping threads during installation.
Black-Oxide Steel—Typically chosen for their appearance, these nuts have a dark, matte coating to create a finished look. They offer minimal corrosion resistance, so they're best for dry environments.
The information in this 3-D model is provided for reference only.