Nylon Insert Lock Nuts Supplier
A standard hex nut backs off under vibration eventually. It's just a matter of when, not if. Valley Nut & Bolt supplies nylon insert lock nuts (also called nylon lock nuts) engineered to grip the bolt thread and stay put through repeated vibration, impact, and cycling. Since 1969, we've sourced and distributed nylon insert lock nuts from our Olympia, Washington warehouse to contractors, fabricators, and OEMs across the Pacific Northwest and nationwide, in the grades, sizes, and finishes each job calls for.
Need Nylon Insert Lock Nuts for Your Next Job?
Stop guessing whether your lock nuts will hold or whether the nylon collar survived galvanizing intact. Send us your spec, drawing, or print, and Valley Nut & Bolt will source the right grade, size, and finish for your application. Request a quote online or call our Olympia, Washington team directly to talk through your fastener needs.
What Is a Nylon Insert Lock Nut?
A nylon insert lock nut is a standard hex nut with a nylon collar molded or pressed into the top of the nut body. As the bolt threads through, the nylon deforms slightly around the fastener, creating friction that resists back-off from vibration or thermal cycling, without relying on torque alone to keep the joint tight. Because the nylon insert grips the thread even before the bearing face contacts the work surface, these are also known as prevailing torque nylon lock nuts, distinguishing them from free-spinning standard nuts.
Unlike all-metal prevailing torque designs, the locking force here comes entirely from the nylon collar, not a deformed or distorted thread. That makes nylon insert lock nuts easier to install and remove by hand while still holding a reliable clamp load in general-duty assemblies.
Nylon Lock Nut Styles We Supply
Not every nylon lock nut fits every joint. We source and stock the following configurations:
The standard configuration, a full-height hex nut body with a nylon collar at the top. This is the most widely specified nylon lock nut for general industrial, construction, and equipment assemblies.
VA lower-profile nut body for low-clearance assemblies where a full-height nut won't seat, while still retaining the nylon locking collar.
Combines a nylon insert with an integrated bearing flange, eliminating the need for a separate washer while adding vibration resistance. If your application calls for load distribution as much as thread lock, see our flange lock nuts page for the full breakdown.
Materials, Grades & Finishes
We source nylon insert lock nuts to match the bolt grade and environment, including:
| Material / Specification | Grades / Types | Typical Use |
|---|---|---|
| Carbon steel nut bodies | Grade 2, Grade 5, Grade 8 — ASTM A563 & SAE J995 | General industrial and structural assemblies matched to bolt grade |
| Stainless steel nut bodies | 18-8 (304), 316 | Corrosion resistance in marine and wastewater environments |
| Alloy steel nut bodies | High-strength alloy grades | High-strength bolted connections |
| Metric sizing | DIN 985 profiles | Metric-spec assemblies and imported equipment |
| Finishes | Plain, zinc-plated, hot-dip galvanized | Corrosion protection suited to indoor, outdoor, or exposed-environment use |
A detail procurement teams often miss: nylon can't survive the heat of the hot-dip galvanizing kettle. Properly made nylon insert lock nuts are galvanized at the steel body stage first, with the nylon collar inserted afterward, so the locking element isn't compromised by process heat. Part of our job as a supplier is knowing which sources build them this way, so you're not stuck with a lock nut that fails the first time it's torqued down.
Where Nylon Insert Lock Nuts Belong (and Where They Don't)
Nylon insert lock nuts perform reliably up to roughly 250°F. Beyond that, the nylon collar softens, loses grip, and the nut becomes a free-spinning fastener again. They're the right call for:
- General industrial and machinery assembly
- Construction and structural connections at moderate temperatures
- Equipment and conveyor systems subject to vibration
- Electrical enclosures, HVAC racking, and fencing hardware
- Applications requiring occasional disassembly and reuse (nylon inserts tolerate a handful of reinstalls before losing effective grip)
If your assembly runs hot, think exhaust systems, engine components, industrial ovens, or high-cycle equipment, the nylon insert isn't the right choice. Our prevailing torque lock nuts use a deformed-thread, all-metal design built for exactly those conditions.
Why Valley Nut & Bolt for Nylon Lock Nuts
- Custom sizing, not just bin stock. Send a spec or drawing and we'll source a run to match, not force-fit an off-the-shelf size.
- Vetted sourcing. We know which manufacturing partners build nylon insert lock nuts correctly, galvanized before nylon insertion, so the locking element performs as spec'd.
- Full traceability. Every order is traceable to the heat, supporting projects that require documented material certs.
- Fast turnaround. Pacific Northwest customers get next-day delivery on our own trucks; we ship nationwide for everyone else.
- One source for the matching hardware. Pair your nylon lock nuts with hex nuts, structural nuts, or all-thread rods from the same supplier.
Looking for a different locking style? Compare flange lock nuts and prevailing torque lock nuts, or return to the full lock nuts overview.
Frequently Asked Questions About Nylon Insert Lock Nuts
Most nylon insert lock nuts are rated for continuous use up to approximately 250°F. Above that range, the nylon collar softens and loses its grip on the bolt thread, which is why high-heat assemblies typically call for an all-metal prevailing torque lock nut instead.
Yes, within limits. The nylon collar can be reinstalled a few times before the thread impression wears down and the locking friction weakens. For assemblies that see frequent disassembly, a fresh nut is the safer call.
A jam nut locks a joint by wedging a second nut against a standard nut using thread friction alone. A nylon insert lock nut achieves the same result with a single nut, using a molded nylon collar to grip the bolt thread, with no second nut required.
Yes. We supply nylon insert lock nuts in 18-8 and 316 stainless steel for corrosive or marine environments, alongside carbon steel and alloy options.
Yes. Send us your spec or drawing and we'll source custom diameters, thread pitches, and metric sizes to DIN 985 profiles, in addition to standard inch sizes.
Ask Our Team
Give us a call or fill out the form and one of our team members will be in touch as soon as possible to answer your questions.
*marks required fields
360-754-4877
