Socket Cap Screws

Socket cap screws are commonly used in machine parts, die fixturing, and clamping. The socket head enables driving where there is not sufficient space for wrenches or sockets.

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.
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

6/6

This is a specific designation of a polyamide or nylon plastic. This lightweight material doesn't have corrosion problems, is non-magnetic, non-corrosive, non-toxic, non-flammable and non-conductive. It is much weaker than the SAE standard grade 2, yet great in low strength applications where weight is at a premium.
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.
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.
A4-80

Made from 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 also slightly stronger than its A4-70 relative. 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.
Class 8.8

This is a metric grading similar to the SAE grade 5 classification, made of medium steel and is of medium strength on the grade scale.
Class 10.9

This is a metric grading similar to the SAE grade 8 classification, which is used in automotive, and structural industries, as well as in high temp applications. Its strength is near the high end of the grade scale, although there are higher grades and strengths for more specialized fasteners.
Class 12.9

This is a very strong metric grading near the top of the grade scale. Similar to grade 9 fasteners it tops out in tensile strength around 180,000 psi., while offering the most strength in a joint. This grade is used in high strength applications.

Material

Alloy Steel

This is the most general term for iron that has been combined with carbon, since all steel has some % of carbon, and at least one other element. Once the steel contains more than a specified threshold amount of a certain element it becomes an alloy. Each element has different threshold values and are used to improve some property of the steel. Common alloying elements are manganese, nickel, chromium, molybdenum, vanadium, and silicon.
Brass

This material has a general composition of 2/3 copper and 1/3 zinc. This material has a distinctive bright golden coloring and is primarily used in aesthetic settings or in applications where low friction is necessary. As an electroplated finish it is nonmagnetic and resists corrosion well. Often used when sparking is an issue. It has excellent cold working (forming at room temperature) properties. Used in locks, gears, doorknobs, plumbing, electrical applications and musical instruments.
Stainless Steel

An iron based material with a minimum of 10.5% chromium. This material is known for its corrosion resistance and has varying strengths depending on the amount of chromium and nickel alloy. The chromium forms a protective layer when exposed to oxygen, keeping the steel underneath from corroding. There are over 150 grades of this material with the 304 and 316 series being the most common.
Steel

The most common material used in fasteners, this material is predominantly iron mixed with carbon. It offers the highest strength compared to other metals and elements, but is the least corrosion resistant. Also known as Carbon Steel.

Thread

Coarse

Also known as UNC/UNRC, it is the most common threading used on bolts, screws and nuts. These threads have faster assembly times, but have less sensitive adjustment. They generally thread easily, yet are slightly weaker than fine threads.
Fine

Also known as UNF/UNRF, this threading is used when higher tensile strengths are needed. These threads have slower assembly times with more sensitive adjustment. They are susceptible to cross threading and are generally stronger than coarse threads.

Type

Socket Cap Screw

Socket cap screws are commonly used in machine parts, die fixturing, and clamping. The socket head enables driving where there is not sufficient space for wrenches or sockets.