Socket Products — Cap Screws & High-Torque Hardware
Socket products are high-strength fasteners driven by an internal hex or spline recess rather than an external wrenched head — engineered for compact spaces requiring high tightening torques, from avionics bays to structural joints where clearance for a wrench simply doesn't exist.
Socket Product Configurations We Manufacture
Socket Head Cap Screws
Cylindrical head with an internal hexagon drive recess — the workhorse configuration for high-clamp-load joints in confined or recessed spaces.
Spline Socket / High-Torque Screws
Twelve-point internal spline recess distributes driving torque across more contact points than a hex socket, reducing recess rounding at very high installation torques.
Overview
Socket products get their name from the internal drive "socket" machined into the fastener head — an internal hexagon or spline recess, rather than an external wrenched surface. This geometry lets a driving tool reach into a counterbored or recessed hole where an external wrench simply couldn't fit, while still delivering very high installation torque thanks to the deep engagement between the driver and the recess walls.
FF-S-86 governs the socket-head cap screw family and is one of the most actively maintained specifications in the entire federal fastener catalog — the current Revision J was published in April 2025. Recent revisions have progressively phased out legacy configurations and hazardous cadmium/hexavalent-chromium finishes in favor of zinc-nickel and hexavalent-chromium-free zinc plating, while adding material options up to Nickel Alloy 718 for high-temperature aerospace and Navy shipboard use.
- Spline-drive sockets are typically reserved for the highest-torque applications, since the twelve-point engagement spreads load more evenly than a six-point hex recess.
- Materials range from general-purpose alloy steel through corrosion resistant steel, silicon bronze (non-magnetic applications), and nickel superalloys for extreme temperature service.
Applicable Standards
Explore the individual socket product specifications Ananka manufactures to.
Socket Products — Frequently Asked Questions
Why choose a socket head cap screw over a hex head bolt?
The recessed internal drive lets the fastener sit inside a counterbore or confined space where an external wrench couldn't engage a hex head, while still delivering high clamp load — common where a low-profile, flush, or space-constrained joint is required.
When would I use a spline socket instead of a hex socket?
Spline sockets distribute driving torque across twelve contact points instead of six, reducing the risk of rounding out the recess at very high installation torques — useful for the highest-strength structural applications.
Is cadmium plating still used on socket products?
Current FF-S-86 revisions mark cadmium and hexavalent-chromium coatings obsolete for new designs, in favor of zinc-nickel or hexavalent-chromium-free zinc plating — legacy cadmium-plated parts may still be sourced for repair/replacement of existing designs.
Need Socket Products to Print?
Ananka Fasteners manufactures socket head cap screws and high-torque hardware with full material traceability and Mill Test Certification on every lot.
Prefer email? sales@anankafasteners.com