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Button Head Socket

Button Head Socket

Button Head Socket

Not sure what size or thread you have or need?

Two ways to confirm before you order - whichever you already know about your fastener.

1If you know the fastener diameter

Open the identification guide ›

2If you have the Allen key

Match your Allen / hex key AF (across-flats) to the screw size it fits. Our reference chart covers every metric and imperial size we stock.

Open the Allen key size chart ›

Button head socket screws provide a larger bearing surface and lower head profile than a standard cap head screw. The wide, low dome sits closer to the surface than a cap head — making them the better choice when material thickness prevents a full cap head recess, or when the fastener head will be visible and appearance matters.

Also known as: Socket Button, Button Allen Head, Button Hex, Allan Bolt, BHSS.

Commonly used in electronics, consumer products, automotive trim, machinery panels and furniture applications where appearance and a flush-looking finish matter. Like all socket screws, they are fully threaded with uniform diameter throughout — they require a pre-tapped hole or matching nut, not a drilled hole.

GRADES AND MATERIALS

Class 12.9 Black (plain finish) — Unfinished bare steel, highest tensile strength. No corrosion protection. For high-load applications in protected environments.

Zinc Plated — Bright silver, internal use. Economical for electronics, general machinery and dry environments.

A2-70 G304 Stainless — The most popular stainless button head. Marked A2, A2-70, 304 or G304. Excellent corrosion resistance. Largely non-magnetic — Small degree of work-hardening magnetism is normal.

A4-70 G316 Marine Grade — For marine, coastal, food and chemical environments. Largely non-magnetic — Same magnetism note applies.

NOTE ON DRIVE TORQUE

The button head hex socket is shallower than a cap head socket of the same thread size, which means maximum installation torque is lower. Do not exceed the recommended torque for button head socket screws — over-torquing can strip the drive recess. For high-torque applications, use a cap head socket screw instead.

WHY AUSTRALIA TRUSTS BOLT & NUT

With 15+ years selling fasteners online from Brisbane, we hold over 25,000 stock lines and 200 million pieces — 98.75% of online orders placed before 1pm leave same day. Save more as you buy more — we offer up to 13 price breaks plus 3 spend-tier discounts. Read our customer reviews or get in touch if you need help picking the right socket screw.

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