J.Lanfranco - Where exceptional quality meets outstanding results.

Performance

Advantages

Confidently reliable performance – set it and forget it.

Quality, performance, and reliability. These are characteristics stamped onto every product we make. From locking ability and interaction with the mating bolt to material quality and corrosion resistance, we observe, refine, and implement all principles of safety-critical bolting to ensure you get a superior product.

Resists vibration, shock, and impact for longer lasting installations.
Quicker and more reliable installations lead to reduced labor and maintenance costs.
Fewer in-service/warranty failures result in lower total cost of ownership.
Non-galling locknuts allow you to save money, reduce labor, and minimize service interruptions/slow-downs caused by seized nuts and damaged bolts.
Reduces wait time with some of the fastest fabrication times in the industry.

How Our Locknuts Work

J.Lanfranco dual-slotted locknuts for safety-critical bolted joints

J.Lanfranco dual-slotted locknuts are based on depitched rather than distorted or deformed threads. As a result, they provide highly-consistent, repeatable, and reliable self-locking torque that’s independent of bolt tension.

Our locknuts preserve surface treatments, won’t damage bolt threads, and will never seize up – even in stainless steel.

Bolt threads expand locking slots located in the turret section of the nut.
Locking slots grip the thread flanks directly where they are designed to support the applied load.
Locking torque is applied evenly over two planes, and on opposite sides.
Once engaged, locking will be effective even with no bolt tension (ideal where low preload is desired).
No galling or thread damage, and resists vibration, shock, and impact.

Surface Treatments

Choose from our wide range of surface treatments for locknuts, washers, bolts, and other weird fasteners.

While some customers order their nuts in a plain finish, most will want some type of corrosion-resistant surface treatment. To meet your various needs and specifications, we offer a huge selection of in-stock parts with different surface treatments: electro-deposited zinc (trivalent and hexavalent), mechanical zinc, zinc flake, and hot-dip galvanized. If you’re not sure which surface treatment is best for your application, contact us and we’ll help you figure it out.

HOT-DIP GALVANIZED

This is the “granddaddy” of surface treatments. Typically stocked in metrics and some limited imperials, all nuts are over-tapped to ensure the best possible fit. If you plan to leave something for 100 years without doing any maintenance, this may be your solution.

Usually, when using a nut/bolt assembly that has been hot-dip galvanized, the nut will be over-tapped (ASTM A563, table 5) to accommodate the additional thickness the HDG will add to the bolt threads. Depending on the precision of your application, it’s advisable to verify the over-tap required to ensure consistent thread fit.

One little-known fact is that European customers will also specify an under-tap on the bolt to maintain standard tapping on the nut. If using metric HDG fasteners, be sure to verify which fastener (nut or bolt) needs to be over- or under-tapped.

STAINLESS STEEL ANTI-GALLING

Plain

Stainless steel, a conventional material widely recognized for its durability and aesthetic appeal.

Passivate

Often preferred by customers working in food and agriculture industries, passivate stainless steel offers a classic finish for any application.

Anti-Galling

The majority of our stainless steel locknuts receive a permanent anti-galling surface treatment which is diffused at 400°C and actually enters the surface of the metal. The result: No galling, no need for anti-seize pastes or lubricants, and guaranteed CoF of 0.15 +/- 0.03. Coupled with our dual-locking slots, seized up installations are a thing of the past.

ZINC FLAKE (LAMELLAR ZINC)

GEOMET:

This is one of the most popular zinc flake coatings today. Available in 320 A & B and 500 A & B, GEOMET is a zinc flake coating that can be applied using a dip/spin method or a rack/hang/spray method. Advantages include very high corrosion resistance (600-1000 hours salt spray) with a thin coating, guaranteed CoF inherent with GEOMET 500 (320 requires the addition of a topcoat), and no risk of hydrogen embrittlement. GEOMET and similar zinc flake coatings are typically used where the risk of hydrogen embrittlement is elevated (when high-strength steel parts are exposed to traditional electro-deposited zinc plating processes).

NOTE:

Despite carrying a high corrosion resistance rating, GEOMET and similar zinc flake coatings should be handled and installed with care to avoid chipping the finish. This will allow corrosion to migrate underneath.

MAGNI 565-575:

This is a very popular zinc flake coating with similar properties as GEOMET and Delta Protekt. Much more prevalent in North America, it typically uses a slightly thicker application.

DELTA PROTEKT:

A popular zinc flake coating available on our fasteners. Minimum lot charges may apply.

Zinc Plate (Hexavalent)

ZINC DICHROMATE PER ASTM B633

Whether in Sc.1-2-3 or types 1-2-3-4-5, we’ve got you covered. A staple for many years, we continue to produce a variety of safety-critical locknuts in this finish. It provides basic but effective corrosion resistance (in the 96 hours to red rust range) in thicknesses that ensure standard thread fit.

OLIVE DRAB, ASTM F1941 D

Although olive drab has become less common in contemporary designs, it still surfaces as a finish choice, resulting in an army green appearance. In order to accommodate legacy designs found in new builds, we continue to offer this option, primarily on nylon insert locknuts ranging from 1/4” to 1-1/4” in stock.

ZINC PLATE (TRIVALENT)

TRIVALENT CLEAR ZINC:

Standard trivalent clear zinc provides basic corrosion resistance of 96 hours salt spray to red rust.

ZINC LANTHANE AND TOPCOAT:

This is our most popular electro-deposited zinc finish and has a clear and shiny appearance. With standard thicknesses of 8-11 microns, it ensures standard thread fit, +600 hours salt spray to red rust performance, and has a guaranteed CoF of 0.15 +/- 0.03. It’s also RoHS and REACH compliant. This is an excellent option for parts requiring good thread fit, consistent CoF, and superior corrosion resistance (compared to traditional zinc finishes).

ZINC NICKEL AND TOPCOAT:

An often overlooked zinc plating, this is an excellent option for areas subjected to debris that will chip or damage surface treatments. It has an average thickness of 8 microns and approximately 12-15% nickel content. This zinc plate will provide a minimum of 750 hours salt spray to red rust performance, while providing a harder surface to withstand the harshest conditions. Also available with a topcoat to provide a guaranteed CoF of 0.15 +/- 0.03. Zinc nickel will show a variety of hues, depending on bath concentration and time in storage. This is normal and will not affect performance.