Holo-krome 68040 Low Socket Cap Screw 5/16-18 Alloy Steel

Product Description

The HOLO-KROME 68040 is a low socket cap screw in the 5/16-18 UNC thread size, measuring 1-1/2 inches in length under head. Made from alloy steel with a black oxide finish, it meets ASME B18.3 and ASTM A574 standards. The low-profile head design provides a reduced head height of 0.1580 inches, making it suited for applications where clearance is limited. Drive is a 5/32-inch hex socket. The fastener is fully threaded along its length. Maintenance technicians, millwrights, and mechanical contractors install this type of screw in assemblies requiring a flush or near-flush head profile with reliable clamping strength.

The 68040 is used in industrial machinery, equipment panels, brackets, and structural assemblies where a standard socket head cap screw would protrude too far. The coarse UNC thread spacing and alloy steel construction make it appropriate for steel-to-steel fastening in manufacturing, MRO, and mechanical service environments. The black oxide finish provides a low-reflectance appearance and mild corrosion resistance in dry or lightly oiled indoor conditions.

Key Features

• Low socket cap head with 0.1580-inch head height for clearance-sensitive installations
• 5/16-18 UNC coarse thread, fully threaded length under head
• Alloy steel construction meets ASTM A574 mechanical property requirements
• 5/32-inch hex socket drive compatible with standard hex keys and drivers
• Black oxide finish for low reflectance and mild corrosion resistance
• Conforms to ASME B18.3 dimensional standard

Compatibility

Designed as an OEM-style and MRO replacement low socket cap screw for 5/16-18 UNC tapped holes requiring a reduced-height head profile per ASME B18.3.

Installation Notes

Install using a calibrated 5/32-inch hex key or socket driver. Ensure the tapped hole is clean and free of debris before threading. De-energize and lock out any equipment before fastener replacement on live machinery per OSHA lockout/tagout procedures. Do not use black oxide fasteners as a primary corrosion barrier in wet or outdoor environments without additional protection.