Hex Cap Screw ASME B18.2.1 UNC/UNF Carbon Steel SAE Grade 2, 5 & 8 Fastener for Automotive and Industrial Machinery

A Hex Cap Screw is a common American-standard fastener used for bolted connections in machinery, vehicles, metal assemblies, and industrial equipment. This product range is specified with ASME B18.2.1, one of the key dimensional standards used for US hex head fasteners.

Buyers can select either UNC or UNF thread series according to the mating part, engineering drawing, or existing assembly requirement. UNC is the coarse-thread option, while UNF is the fine-thread option. Specifying the correct thread series helps ensure the cap screw matches the required nut, threaded hole, or replacement part.

SAE Grade 2, Grade 5, and Grade 8 options are available upon request. The selected grade should match the required mechanical performance level of the automotive or industrial assembly.

Product Specifications

UNC and UNF Thread Options

UNC and UNF thread selection is one of the most important details when purchasing US Standard Hex Cap Screws.

UNC refers to Unified National Coarse thread. It is commonly specified for standard fastening connections where the matching part requires a coarse-thread screw.

UNF refers to Unified National Fine thread. It is selected when the drawing, nut, threaded hole, or existing equipment requires a fine-thread specification.

For replacement orders, buyers should provide the bolt diameter, threads per inch, thread series, and overall length. This reduces the risk of ordering a cap screw that does not match the existing connection.

SAE Grade 2, Grade 5 and Grade 8 Options

This product is available in SAE Grade 2, Grade 5, and Grade 8 options.

SAE Grade 2 is available for buyers whose drawings or existing assemblies specify Grade 2 fasteners.

SAE Grade 5 is available for automotive, equipment, and industrial customers requiring a Grade 5 specification.

SAE Grade 8 is available for applications where the drawing or mechanical requirement specifies Grade 8 fasteners.

When requesting a quotation, the required SAE Grade should be stated clearly. Grade 2, Grade 5, and Grade 8 should not be treated as interchangeable, because the selected grade needs to match the application requirement.

Applications

US Standard Hex Cap Screws are suitable for fastening requirements in automotive production, vehicle repair, machinery assembly, industrial maintenance, and equipment manufacturing.

Typical uses include:

Automotive brackets, frames, covers, and mounting components

Agricultural machinery and heavy equipment assemblies

Industrial machine bases, guards, and support structures

Manufacturing equipment installation and maintenance

Metal fabrication and mechanical assembly

OEM production and replacement fastener supply

North American standard machinery and equipment servicing

Distributor, wholesaler, and MRO fastener programs

Information Needed for an Accurate Quote

To prepare a correct quotation for ASME B18.2.1 Hex Cap Screws, please provide the following information:

Required thread diameter

UNC or UNF thread series

Threads per inch, if known

Overall screw length

SAE Grade 2, Grade 5, or Grade 8

Required material or surface finish

Quantity required

Application or equipment type

Requirement for matching nuts, washers, or packaging

Providing the thread series and grade at the beginning helps prevent specification errors and makes the quotation process faster.

FAQ

1.What is the standard for this Hex Cap Screw?

This product is specified for ASME B18.2.1 requirements, which is commonly used for US Standard hex head fasteners.

2.What is the difference between UNC and UNF?

UNC is a coarse-thread series, while UNF is a fine-thread series. The correct option depends on the engineering drawing, mating nut, threaded hole, or existing equipment requirement.

3.Which SAE Grades are available?

SAE Grade 2, Grade 5, and Grade 8 options are available upon request.

4.Can I use Grade 5 instead of Grade 8?

The selected grade should follow the product drawing, assembly requirement, or equipment specification. Grade substitution should only be made when it is approved for the application.

5.What information should I provide for a replacement order?

Provide the screw diameter, length, UNC or UNF thread type, threads per inch if available, SAE Grade, quantity, and a photo or drawing if possible.

6.Can you supply matching nuts and washers?

Matching nuts, washers, and related fastening accessories can be discussed according to the required assembly configuration.

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NeedUS Standard Hex Cap Screwsfor automotive production, machinery assembly, maintenance, or replacement supply? Send us yourASME B18.2.1requirement, UNC or UNF thread series, diameter, length, SAE Grade, quantity, and application details.

For fast quotation support, include the requiredGrade 2, Grade 5, or Grade 8specification together with any requirement for matching nuts, washers, surface finish, or packaging.