Value Collection 211021PR Flat Socket Cap Screw 4-40

Product Description

The VALUE COLLECTION 211021PR is a 4-40 x 3/4-inch flat socket cap screw designed for applications requiring a flush or countersunk fastener profile. Manufactured from alloy steel with a black oxide finish, this screw delivers solid mechanical strength and moderate corrosion resistance in a compact form factor. The 82-degree flat head seats flush with the workpiece surface when driven into a properly chamfered hole. Drive engagement is via a 1/16-inch hex socket. The screw is fully threaded along its entire 3/4-inch overall length, maximizing thread engagement in thin or shallow-tapped materials.

This fastener is suited for light-gauge metal assemblies, precision enclosures, brackets, and machine components where a low-profile or flush head is required. The 4-40 UNC thread is a common fine-pitch size found in instrumentation, electronic enclosures, small motors, and control panel hardware. It is typically installed by machinists, assembly technicians, electricians, and HVAC service professionals working with panel or equipment chassis fastening. The black oxide finish blends with black anodized or painted surfaces and provides mild surface protection in dry or lightly oiled environments.

Key Features

• 82-degree flat head seats flush in standard countersunk holes
• 1/16-inch hex socket drive for precise torque application in tight spaces
• Fully threaded 3/4-inch overall length for maximum thread engagement
• Alloy steel construction provides high tensile strength for the 4-40 size class
• Black oxide finish reduces light reflection and offers mild corrosion resistance
• Meets ASME/ANSI B18.3 and ASTM F835 fastener standards

Compatibility

Designed as a standard 4-40 UNC flat socket cap screw per ASME/ANSI B18.3, compatible with any 4-40 UNC tapped hole requiring an 82-degree countersunk flat head fastener.

Installation Notes

Installation requires a 1/16-inch hex key or hex bit driver. The mating hole must be countersunk to 82 degrees to achieve a proper flush seat. Power down any electrical equipment before fastening or removing hardware on live panels or enclosures. Avoid over-torquing, as the 4-40 thread is a small-diameter fastener with limited torque capacity.