Cheap 5/16-18 X 3/4″ Socket Cap Screws Flat Head Hex Socket Drive Alloy Steel Thermal Black Oxide (200 / Pkg.)

Cap Screws Flat Socket Alloy Thermal Black Oxide 5/16-18 x 3/4 are engineered to deliver high-strength, reliable fastening in a compact form factor. The flat socket head sits flush in countersunk recesses, reducing snagging and enabling a clean appearance in precision assemblies.

Designed for demanding environments, these cap screws are made from alloy steel for superior strength and durability. The thermal black oxide finish enhances corrosion resistance and provides a discreet, anti-glare surface suitable for machinery and automotive applications.

Specifications

Head style: Flat Socket (socket cap) head

Material: Alloy steel

Finish: Thermal Black Oxide

Thread: 5/16-18 UNC

Length: 3/4 inch

Drive: Hex drive (Allen key)

Applications

Ideal for automotive assemblies, machinery, equipment maintenance, and any project requiring strong, flush-head fasteners with a corrosion-resistant finish. Great for applications where a low-profile head is essential or where clearance around the head matters.

Installation Tips

Choose the correct hex key size to avoid stripping the drive.

Ensure proper threading and alignment to prevent cross-threading.

Lubricate the threads if using in high-vibration or load-bearing applications to reduce galling.

For torque guidelines and compatibility, refer to your equipment’s specification sheet.