Lock Washers

Lock washers are specially designed to keep threaded fasteners from loosening. They prevent vibrations and some have external teeth to prevent rotation. These washers are often found in airplanes and in structural applications.

Finish

Black Oxide

An extremely thin attractive finish with minimal corrosion resistance. This coating reduces galling, improves lubrication of mating parts and reduces glare. This finish looks great when trying to achieve a stylish or "high-tech" look on exposed fastener heads.
Chrome

This finish improves appearance and provides mild corrosion resistance. It can also increase surface hardness, which improve abrasion resistance, reduces friction, and prevents seizing. This finish is shiny and aesthetically pleasing.
Delta Protekt®

This silver finish is based on zinc coatings and offers extreme corrosion resistance with minimal thickness. It is used on high quality steels and eliminates the risk hydrogen embrittlement. This finish also has zero harmful elements including hexavalent chromium. A good choice for outdoor exposure like Hot Dipped Galvanized coating except much thinner for tighter tolerances.
Plain

Nothing has been done to this bare metal surface to improve appearance or corrosion resistance, which is very low if the material is steel. Often the surface has been oiled which improves lubricity. This finish is susceptible to rusting and corrosion in exterior environments. This most basic finish can be used when protection is not an issue or indoors.
Yellow Zinc

This iridescent electroplated zinc finish, also known as Yellow Zinc Chromate or Dichromate, provides very good corrosion resistance and protection against rust. This finish should not be used in marine or high salt spray environments.
Zinc

This finish, also know as zinc plating, zinc chromate or dichromate provides good corrosion resistance and is the standard for many hardware fasteners. It is an electroplated zinc layer covered with a chromate post-treatment. The zinc protects the steel from corrosion and the chromate layer protects the zinc from degrading. It is a popular finish because of its protection, value, and ease of coating. Slightly less corrosion resistant than yellow zinc, it is a versatile finish that is best used indoors. This finish should not be used in marine or high salt spray environments.

Material

Aluminum

Aluminum fasteners are a light weight alternative to steel fasteners. Aluminum is soft, non-magnetic, and corrosion resistant. These fasteners offer good electrical and thermal conductivity, and a good strength-to-weight ratio.
High Alloy Steel

High alloy steels contain a higher percentage of alloying elements in addition to carbon, giving the steel special properties. Many high alloy steels are stainless steels, which are resistant to corrosion.
Monel

This 2/3 nickel and 1/3 copper material is an alloy developed by the Special Metals Corporation. It has very good strength and is similar in strength to medium carbon steel, however, due to its strength it has poor machining properties. Its composition also provides it with excellent corrosion resistance in specific highly corrosive environments of sea water, hydrofluoric acid, sulfuric acid, alkalines. With the ability to retain its strength at very high and low temperatures it is one of the best materials to resist extreme elemental conditions. Applications include marine fasteners and chemical processing.
Silicon Bronze

Silicone bronze is a high strength fastener material popular in naval and marine environments, and sewage disposal applications. Silicon bronze is known for its high thermal conductivity, non-magnetic properties, and high resistance to corrosion, even in harsh environments such as those where brines or gases are present.
Stainless Steel

Stainless steel is steel combined with alloying elements, principally chromium, to enhance corrosion resistance and impart other desired properties depending upon the alloying elements in use and their proportions. Many stainless steel fasteners are non-magnetic or less magnetic than regular steel fasteners.
Steel

Steel is the most common fastener material due to its strength properties. Unalloyed steel may be surface treated to enhance corrosion resistance and other desirable properties.

Style

High Collar

This style of washer, also known as spring lock or split lock, is circular with a single radial cut. One side of this cut is bent up and the other down. The washer locks a nut in place by exerting force from this deformation into the bottom of the fastener head and the fastened surface. This lighter duty class has the thickness of a medium duty split lock washer with the outer diameter of the light duty. This washer offers medium locking power and should be used in medium strength applications. Often used with hex cap screws when side clearance is an issue.

Type

Split Lock Washer

For use with hard surfaces, split lock washers help the screw resist loosening from vibration by exerting tension between the fastener head and mating surface under compression.