STAINLESS STEEL LANFRANCO ESL LOCKING NUTS

LanFranco ESL Locking Nuts — LanFranco ESL Locking Nuts are an all-metal self-locking nut from French manufacturer J. Lanfranco, developed as a metal-to-metal alternative to a nylon insert (nyloc) nut wherever heat, chemical exposure, or repeated reuse would degrade a nylon locking element. Like other all-metal self-locking nuts, the ESL range achieves its prevailing-torque lock through a deformed or elliptical thread section, or an engineered friction-collar effect built into the nut body, rather than through any separate plastic insert. That makes it a natural fit for under-bonnet automotive assemblies, exhaust and manifold fixings, furnace and oven equipment, process plant, and any joint that sees sustained heat, oil or solvent exposure, or frequent disassembly during maintenance — conditions that would shorten the working life of a standard nylon locknut. As with any all-metal locking fastener, the trade-off against a nylon insert nut is cost and installation torque: an ESL nut typically needs a higher running torque to engage its lock, and the extra expense over a standard nyloc is worth paying specifically where operating temperature, chemical environment, or reuse frequency would otherwise compromise a nylon element — for a cool, dry, rarely-disturbed joint, a standard nylon insert nut usually remains the simpler and more cost-effective choice. Sizing follows the same metric thread and across-flats conventions as other standard hexagon nuts, so selection is mainly about matching thread diameter and pitch to the mating bolt and confirming the correct grade and finish for the application. Because ESL is a proprietary design rather than a nut built to a published DIN or ISO locking-nut standard, the exact locking mechanism details are best confirmed against the manufacturer's own documentation for a given application, but the underlying principle is the same as other all-metal self-locking nuts.

FAQs
What does "ESL" refer to?
ESL is the model designation LanFranco uses for this all-metal self-locking nut range, distinguishing it from the company's other nut lines.

Is the LanFranco ESL locking nut reusable?
All-metal self-locking nuts are generally designed for more reuse cycles than nylon insert nuts, though this depends on the specific design and application. As with other all-metal locknuts, some reduction in locking torque should be expected after repeated removal and refitting, so reuse should be assessed against the specific application's requirements.

Does an ESL nut need more torque to install than a standard nut?
Yes. Because the lock is generated by a deformed thread section or friction-collar effect gripping the bolt thread, running torque during installation is higher than for a plain full nut of the same size — this is a normal characteristic of all-metal locknuts and should be allowed for when specifying tooling.