Cone Lock Nuts
What Are Cone Lock Nuts?
Cone lock nuts—also called Stover lock nuts or all-metal prevailing torque nuts—use a conical, distorted-thread section at the top of the nut to create friction on the bolt’s threads. This built-in interference produces a reusable, high-vibration lock without nylon inserts or liquid threadlocker, and it continues to hold at elevated temperatures.
Key Benefits of Cone Lock Nuts
- Vibration resistance: Prevailing torque keeps joints tight where standard hex nuts can loosen.
- All-metal design: No nylon to soften or degrade in heat, oils, solvents, or UV.
- Reusable in many assemblies: Elastic thread distortion provides repeatable locking (replace in critical service if torque falls outside spec).
- Simple, one-piece solution: No separate lock washer or adhesive required.
Cone Lock Nut Materials & Grades
- Zinc-plated carbon steel: Economical corrosion protection for dry, indoor, or sheltered outdoor use.
- Plain (black) carbon steel: Best where finish is not required or parts will be coated post-assembly.
- Metric DIN 980V / Imperial Grades: Offered across common strength classes to match your bolt grade. Always pair nut strength with the fastener’s grade.
Common Applications for Cone Lock Nuts
- Automotive, truck, and off-highway equipment
- Industrial machinery and vibration-prone assemblies
- Construction hardware and structural fittings (non-welded joints)
- Aerospace/industrial panels, guards, and fixtures
How to Install Cone Lock Nuts
- Orient the nut with the conical, distorted end up (away from the bearing surface).
- Run the nut down by hand until resistance from the prevailing torque is felt.
- Tighten to the specified torque using a wrench or socket. Do not lubricate unless your specification provides adjusted torque values.
- For safety-critical joints, verify prevailing-torque values on first installation and after any reuse.
How to Select the Right Cone Lock Nut
- Match thread size & pitch: e.g., 1/4-20, 3/8-16, M10-1.5.
- Match strength class: Choose a nut grade that equals or exceeds the bolt grade.
- Choose finish for environment: Zinc-plated for general use; plain steel for post-coating or dry interiors.
- Temperature & chemicals: Use all-metal cone locks where nylon insert nuts are unsuitable.
Frequently Asked Questions about Cone Lock Nuts (FAQ)
To provide a reusable, vibration-resistant lock in machinery, vehicles, and equipment without nylon inserts or liquid threadlocker.
Install with the distorted, conical end away from the bearing surface. The flat end bears against the joint; the conical end creates the locking friction.
Often yes, because the distortion is elastic. For safety-critical service, measure prevailing torque and replace if it falls outside spec.
Use cone lock nuts for high temperature, chemical exposure, or where oils/solvents/UV could affect nylon. Use nylon insert nuts for general ambient assemblies.
Follow the joint design or fastener standard for the specific grade/size. Do not add lubrication unless torque values are adjusted accordingly.
Zinc-plated for economical corrosion resistance; plain steel for dry interiors or when parts will be painted, plated, or coated after assembly.