Holo-krome 72148 Hex Socket Cap Screw 5/16-18 Unc

Product Description

The HOLO-KROME 72148 is a hex socket cap screw designed for high-strength fastening applications in mechanical assemblies, industrial equipment, and structural connections. It features a 5/16-18 UNC thread and measures 3.5 inches under the head, with partial threading along the shank. The drive is a 1/4-inch internal hex socket, requiring an Allen or hex key for installation and removal. Constructed from alloy steel with a black oxide finish, this fastener delivers good tensile strength and moderate corrosion resistance. It conforms to ASME B18.3 and ASTM A574 standards, making it suitable for demanding mechanical and industrial environments.

This screw is used across a broad range of trade and industrial applications including HVAC equipment assembly, pump and compressor mounting, panel fabrication, and general mechanical maintenance. The 5/16-18 UNC coarse thread is one of the most common thread pitches in North American mechanical work, and the 3.5-inch length under head suits medium-depth through-bolting and tapped-hole fastening. The black oxide finish reduces surface reflectivity and provides mild rust resistance in dry or lightly humid indoor environments. Sold individually with a minimum order quantity of 50 pieces.

Key Features

• 5/16-18 UNC coarse thread for broad compatibility with standard tapped holes and nuts
• 3.5-inch length under head for medium to deep fastening applications
• Partially threaded shank provides a smooth bearing surface and improved shear strength
• 1/4-inch internal hex socket drive for torque application with standard Allen keys
• Alloy steel construction meets ASTM A574 high-strength requirements
• Black oxide coating reduces glare and provides light corrosion resistance in dry conditions

Compatibility

Designed as an OEM-style replacement or standard-use hex socket cap screw for any application requiring a 5/16-18 UNC partially threaded fastener conforming to ASME B18.3 and ASTM A574.

Installation Notes

Installation is typically performed by mechanical technicians, millwrights, or trade professionals using a calibrated torque wrench with a 1/4-inch hex bit. Always de-energize and lock out equipment before servicing fastened assemblies per applicable OSHA lockout/tagout procedures. Do not reuse fasteners that show signs of thread damage, galling, or deformation. Apply thread lubricant or anti-seize compound only if specified by the equipment manufacturer, as this affects torque-to-clamp-load relationships.