Flat Countersunk

Flat Head Cap Screws: When flush mounting is essential, our flat head cap screws rise to the occasion. Their countersunk heads ensure a smooth, even surface, ideal for applications where protrusions are undesirable.

Flat countersunk head cap screws are manufactured to various specifications and standards to ensure their quality, compatibility, and performance in different applications. Some of the key specifications and standards include:

The key features of flat countersunk head cap screws include:

  1. Flat Head: The head of the screw is flat, providing a smooth surface when installed. This design minimizes protrusions and allows for a flush finish, making it suitable for applications where aesthetics or surface smoothness are important.
  2. Countersunk Recess: The top of the head is designed with a conical-shaped recess (countersink) that allows the screw to be flush with or below the surface of the material being fastened. This recess accommodates the tapered shape of the screw head and ensures a secure fit when installed.
  3. Hexagonal Socket Drive: Flat countersunk head cap screws typically feature a recessed hexagonal socket drive on the underside of the head. This drive type requires the use of a corresponding hex key or Allen wrench for installation and provides a secure grip for tightening the screw.


Flat countersunk head cap screws are a type of fastener characterized by a flat head with a conical-shaped recess (countersink) on the top and a cylindrical shaft with a recessed hexagonal socket drive (often referred to as an Allen drive) on the underside. This design allows the screw to sit flush or below the surface of the material being fastened when fully installed.

  1. ASME B18.3: This standard, published by the American Society of Mechanical Engineers (ASME), provides dimensional and performance requirements for socket head cap screws, including flat countersunk head cap screws. It covers details such as thread size, thread pitch, head dimensions, and material properties.
  2. ISO 10642: This is the International Organization for Standardization (ISO) standard for hexagon socket countersunk head screws. It specifies dimensions, tolerances, and technical requirements for these fasteners, ensuring interchangeability and compatibility across different manufacturers.
  3. ASTM F879: ASTM International publishes this standard, which covers the requirements for stainless steel socket flat countersunk head cap screws. It specifies the chemical composition, mechanical properties, and other relevant characteristics of stainless steel screws suitable for use in corrosive environments.
  4. DIN 7991: This is the German Institute for Standardization (DIN) standard for flat countersunk head screws with hexagon socket. It provides detailed specifications for dimensions, tolerances, and material requirements, widely used in European markets.
  5. Customer-specific Requirements: In addition to industry standards, flat countersunk head cap screws may also be manufactured to meet specific requirements specified by customers, particularly in specialized applications or industries with unique demands.

By adhering to these specifications and standards, manufacturers ensure that flat countersunk head cap screws meet the necessary quality and performance criteria, providing reliable fastening solutions across a wide range of applications.