Value Collection 581978BR Hex Socket Cap Screw 1-3/4-5 Unc

Product Description

The VALUE COLLECTION 581978BR is a partially threaded hex socket cap screw designed for heavy-duty fastening applications in industrial, mechanical, and structural assemblies. It features a 1-3/4-5 UNC thread size and a 5-1/2 inch length under head, with a 1-1/4 inch hex drive socket. Manufactured from alloy steel and finished with a black oxide coating for corrosion resistance, this fastener meets ASME/ANSI B18.3 and ASTM A574 standards. It is installed using a standard hex socket or Allen-type driver and is suited for high-strength bolted connections requiring a recessed drive configuration.

This screw is appropriate for use in manufacturing equipment, machine frames, fixtures, dies, and heavy mechanical assemblies where a flush or countersunk head profile and high clamp load are required. The coarse UNC thread pitch is well-suited for use in steel and alloy components where quick engagement and resistance to loosening under vibration are priorities. Partially threaded shanks provide a smooth bearing surface through clearance holes for improved joint integrity.

Key Features

• 1-3/4-5 UNC coarse thread for strong engagement in steel and alloy materials
• 5-1/2 inch length under head accommodates thick workpieces and stacked assemblies
• 1-1/4 inch hex socket drive for high-torque installation with standard hex drivers
• Partially threaded shank provides a smooth bearing surface through clearance bores
• Alloy steel construction meets ASTM A574 high-strength fastener requirements
• Black oxide finish adds surface corrosion resistance and reduces light reflection

Compatibility

Designed as a standard ASME/ANSI B18.3 and ASTM A574 compliant hex socket cap screw for use in heavy industrial and mechanical fastening applications requiring a 1-3/4-5 UNC thread form.

Installation Notes

Installation is typically performed by machinists, millwrights, or mechanical assembly technicians. Use a calibrated torque wrench with a 1-1/4 inch hex bit to achieve proper clamp load without overloading the fastener. Ensure mating threaded holes or nuts are clean and free of debris before installation. Verify thread engagement depth meets the minimum requirements specified in the applicable equipment or structural design documentation.