Hex cap screws are manufactured to dimensional standards of ASME B18.2.1 and to various material and mechanical standards of ASTM and SAE. The length of a cap screw is measured from under the head to the extreme end of the screw. The standard thread length is two times the diameter plus 1/4" up to 6" length and two times the diameter plus 1/2" for screws longer than 6". Shorter length screws are fully threaded. Product standards require the manufacturer's head marking to appear on the top of all hex cap screws 1/4" diameter and larger. Hex Head Cap Screws, Plated are available in Grade 2, Grade 5 & Grade 8 Steel.
Please see Hex Cap Screw Technical information below for materials, head & thread dimensions.
A low or medium carbon steel, externally threaded mechanical device 1/4” diameter or larger, with a trimmed hex head and a washer face on the bearing surface.
Grade 2 (A307A) Hex Cap Screw Applications
Grade 2 (A307A) Cap Screws are made from low carbon steel that achieve their strength primarily from cold working during the cold forming manufacturing operation. Economical for use in non-critical applications where the fastener is not subject to extreme temperatures or stress.
Grade 5 Hex Cap Screw
A cap screw made from medium carbon steel and heat-treated.
Grade 5 Hex Cap Screw Applications
Grade 5 (A449) Cap Screws are medium strength fasteners that achieve their strength from a quench and temper heat treatment and have a greater tensile strength than a Grade 2. Yield-to-tensile ratio is the lowest of all heat-treated steels.
Grade 8 Hex Cap Screw
A cap screw made from medium carbon alloy steel and heat-treated
Grade 8 (A307A) Hex Cap Screw Applications
Grade 8 (A354 GR BD) Cap Screws are the highest strength of standard inch series cap screws and are made from alloy steel and have greater tensile strength than Grade 5. Designed for use in high stress applications.
18-8 & 316 Stainless Steel Hex Cap Screw
18.8 and 316 stainless steel cap screws manufactured from austenitic alloys.
18-8 & 316 Stainless Steel Hex Cap Screw Applications
18-8 stainless steel screws are used in products that require general atmospheric corrosion resistance, such as chemical, food and drug equipment, bearing plates, heat exchanger tubes, pumps and valves.
The molybdenum content of 316 stainless steel screws give them a higher resistance to corrosion and superior strength at high temperatures. Common uses for 316 stainless steel screws include exhaust and furnace parts, jet engine parts, pharmaceutical and photographic equipment, pump parts, chemical processing equipment, tanks, and evaporators. It also is used in pulp, paper, and textile processing equipment and any parts exposed to marine environments.