Jam Nuts

Jam nuts are used as a second nut threaded over a bolt to prevent the first from loosening, or in applications where there is not sufficient space for a standard nut.

Finish

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.

Grade

2H

This is a high pressure and temperature grade nut made of medium carbon steel that has been quenched and tempered. This grade meets ASTM specification A 194. These nuts are also used in flanges and fittings as well as in heavy construction of buildings and bridges.
5

This grade is from the SAE scale. Made of medium to low carbon steel, it is of medium strength on the grade scale.
17H

This is a European carbon steel property class based off of the Vickers Hardness Scale, that has restrictions on Carbon [0.50% max), Phosphorus (0.12% max), and Sulphur (0.34% max). It is a class designated by ISO 898-5, which very specifically applies to fasteners not under tensile stress.
18-8

A general designation for the most common and popular stainless steel, (300 Series) referring to the 18% chromium and 8% nickel. It's strength has a range from the middle to low end of the grade scale. All 300 series stainless steel share the ratio of chromium to nickel with varying other elements improving different properties. It has higher corrosion resistance than the 400 series stainless steels and it is non-magnetic.
316

The second most common stainless steel grade, this material is stronger than grade 2, slightly weaker than grade 5,or generally as strong as medium to low carbon steel. It is on the low middle end of the grade scale. It is used in more severe corrosive environments than 304 stainless steel, as such it is used in more industrial settings, like process chemicals, textiles, bleaches, salt water and rubber. It is also used in surgical implants. The DIN/ISO denotation for a very similar grade is A4-70.
A

This grade is used in low strength applications. This grade meets ASTM specifications for A563 and is typically used with ASTM Grade A and B bolts or SAE grade 1 and 2 bolts.
A2-70

A type of the most common stainless steel grade. It is comparable in strength to grade 2 materials, yet slightly weaker and easy to weld. This grade is always metric. The ASTM denotation for very similar grade is 304. The corrosion resistance and ease of fabrication are why this grade is used in food industry machines, appliances, architectural trim and aquatic fasteners.
A4-70

The second most common stainless steel grade, this material is stronger than grade 2 and generally as strong as medium to low carbon steel. It is on the low middle end of the grade scale. This grade is always metric. The ASTM denotation for a very similar grade is 316.
Alloy 651

This predominantly copper alloy of medium to high strength is superior to medium strength steel. In addition it has excellent hot and cold working characteristics with very good corrosion resistance. Also known as Low Silicon Bronze.

Material

Brass

Brass is a soft, non-magnetic fastener material that offers corrosion resistance, heat and electrical conductivity, and cosmetic appeal. Brass fasteners may be found in electronics, plumbing, and marine applications.
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.

Specification

ASTM A194

Meets ASTM standards for hex nuts for a certain range of sizes, metric and Imperial.
ASTM A563

Meets ASTM chemical, mechanical and dimensional standards for several grades of steel nuts.
ASTM F594

Meets ASTM standards for stainless steel nuts with interior diameters ranging from 1/4 to 1-1/2 inches.
DIN 439B

Meets German standards for hexagonal metric jam nuts.
DIN 936

Meets German standards for hexagonal metric jam nuts size M8 to M52 and size M8x1 and M52x3.
SAE J995

Meets SAE standards for steel nuts.

System of Measurement

Metric

Also known as the SI system, this measurement system is used across the globe. It is based on multiples of ten and uses meters, centimeters, millimeters as its basic measurements.

Type

Jam Nut

Jam nuts are used as a second nut threaded over a bolt to prevent the first from loosening, or in applications where there is not sufficient space for a standard nut.
Jam Nut - Heavy

This style of nut refers to its superior design strength compared to other nuts of similar size and grade. This jam nut is slightly larger, stronger and more durable than the average nut and is therefore termed "heavy".
Jam Nut - Left Hand

Left handed nuts, or reverse thread nuts, pair with left handed bolts. These are used in applications in which rotation would cause right handed connections to loosen.