5/16"-18 UNC A2 Stainless Socket Button Head Screws

Product Description

5/16"-18 UNC A2 stainless steel socket button-head machine screws with a low-profile rounded head and internal hexagon drive.

These imperial Allen screws combine a broad button head with a coarse Unified thread. The smooth, shallow head provides a neat finished appearance with less projection than a conventional socket cap screw, making them suitable for panels, brackets, guards, machinery and general engineering assemblies.

• Thread size: 5/16"-18 UNC
• Threads per inch: 18 TPI
• Thread series: UNC – Unified National Coarse
• Nominal major diameter: 5/16" / approximately 7.94mm
• Head style: Low-profile rounded socket button head
• Nominal head diameter: Approximately 0.547" / 13.89mm maximum
• Nominal head height: Approximately 0.166" / 4.22mm maximum
• Drive type: Internal hexagon / Allen key
• Nominal Allen key size: 3/16"
• Material: A2 stainless steel
• Finish: Natural stainless steel
• Dimensional reference: ASME B18.3 inch-series socket button-head pattern
• British Standard: No specific BS verified for this button-head pattern

These 5/16" UNC socket button-head screws are suitable for machinery, automotive components, guards, panels, brackets, furniture, electrical equipment, fabrication and general engineering applications.

The 18 TPI Unified National Coarse thread provides a robust imperial machine-screw connection. The mating nut, threaded insert or tapped hole must have the corresponding 5/16"-18 UNC thread.

The broad rounded button head provides a lower-profile finish than a conventional cylindrical socket cap head. This can reduce protrusion above the assembled surface and provide a smoother, more decorative appearance.

Button-head screws generally have a smaller hexagon drive and a lower maximum tightening capacity than equivalent standard socket cap screws. They should not automatically be substituted for standard socket cap screws in highly loaded joints without checking the application requirements.

The internal hexagon drive is operated with a nominal 3/16" Allen key or hex socket bit. Use a correctly sized, good-quality tool fully inserted into the recess to reduce the risk of rounding or damaging the socket.

A2 stainless steel provides good resistance to general atmospheric corrosion and is suitable for many indoor and outdoor applications. For marine, coastal, swimming-pool or highly corrosive environments, A4 stainless steel may be more appropriate.

Stainless steel threads can be susceptible to galling, particularly when installed rapidly, overtightened or assembled without lubrication. Where appropriate, use a compatible anti-seize compound, keep the mating threads clean and tighten at a controlled speed.

Button-head screw length is measured from directly beneath the head to the end of the screw. The rounded head is not included in the stated length.

Please note: ASME B18.3 is used as the dimensional reference for this inch-series socket button-head pattern. The listed head and socket dimensions are nominal standard dimensions and may vary within permitted manufacturing tolerances. Available lengths, pack quantities and thread coverage should be added once the final product variants have been confirmed.

Please Note: Specifications given are intended as a guide only. If critical to your project please check with us first.