Value Collection 581881BR Hex Socket Cap Screw 1-1/8-7 Unc

Product Description

The VALUE COLLECTION 581881BR is a partially threaded hex socket cap screw designed for heavy-duty fastening applications. Manufactured from alloy steel with a black oxide finish, this fastener delivers high tensile strength and moderate corrosion resistance in a compact, recessed-drive format. The screw features a 1-1/8-7 UNC thread size and measures 8 inches in length under the head, making it suitable for thick-section assemblies and structural bolted joints. It is driven with a 7/8-inch hex key. Meets ASME/ANSI B18.3 and ASTM A574 standards, which define dimensional tolerances and mechanical requirements for socket cap screws.

This fastener is used across a broad range of industrial and mechanical assembly applications. Typical installations include machine frames, jigs and fixtures, die sets, hydraulic equipment, and structural steel assemblies where a flush or low-profile head is required. The partially threaded shank provides a smooth bearing surface that resists shear loads and allows precise clamping without thread engagement through the full grip length. Millwrights, machinists, and maintenance mechanics commonly specify this type of fastener in manufacturing and heavy equipment environments.

Key Features

• 1-1/8-7 UNC thread form for use with standard UN tapped holes
• 8-inch length under head accommodates thick-section or stacked assemblies
• Partially threaded shank provides shear resistance and controlled clamp length
• 7/8-inch hex drive for high-torque installation with a standard hex key
• Black oxide finish reduces light reflection and offers mild corrosion resistance
• Meets ASME/ANSI B18.3 and ASTM A574 for dimensional and mechanical compliance

Compatibility

Designed for use in 1-1/8-7 UNC tapped holes in machine structures, fixtures, and mechanical assemblies requiring a socket head cap screw profile per ASME/ANSI B18.3.

Installation Notes

Installation is typically performed by machinists or millwrights using a calibrated torque wrench with a 7/8-inch hex bit. Always verify that the tapped hole depth and thread engagement length meet ASME or applicable engineering specifications before torquing. De-energize and lock out all equipment before accessing any fastener locations on powered machinery. Inspect the fastener and mating threads for damage or contamination prior to assembly.