Value Collection MSRI0-400870-100BX 4-40 X 7/8 in Round Head Screw

Product Description

The VALUE COLLECTION MSRI0-400870-100BX is a 4-40 unified coarse thread machine screw designed for precision fastening in light mechanical assemblies. It features a round head profile and slotted drive, making it compatible with standard flat-blade screwdrivers. Manufactured from alloy steel with a zinc-plated finish, it provides corrosion resistance suitable for indoor and light-duty applications. At 7/8 inches in length measured under the head and a nominal thread diameter of No. 4, it fits common tapped holes in sheet metal, electronic enclosures, and small equipment housings. This fastener meets ASME B18.6.3 dimensional standards. Sold in a minimum order quantity of 100 pieces per box.

This machine screw is suited for use in electrical panels, HVAC control boards, small appliance housings, and precision instrument enclosures where a low-profile round head and slotted drive are required. It is a standard inch-system fastener and is commonly specified by electricians, HVAC technicians, and mechanical assemblers working on equipment that calls for a 4-40 threaded fastener without a washer face. The zinc plating makes it appropriate for dry or mildly humid indoor environments.

Key Features

• 4-40 unified coarse thread for use in standard tapped holes and threaded inserts
• Round head profile with slotted drive accepts standard flat-blade screwdrivers
• Alloy steel construction provides strength suitable for light mechanical and electrical assembly
• Zinc-plated finish for corrosion resistance in indoor environments
• 7/8 inch length measured under the head per ASME B18.6.3
• No washer face — clean seating against flat surfaces

Compatibility

Designed as a standard inch-system machine screw for any application requiring a 4-40 threaded fastener with a round head and slotted drive, conforming to ASME B18.6.3 dimensional requirements.

Installation Notes

Install with a flat-blade screwdriver sized to fit the slot without slipping, which can damage the head or surrounding material. Ensure the mating tapped hole or threaded insert is clean and free of debris before driving. Do not overtighten small-diameter machine screws, as alloy steel fasteners at No. 4 size can shear if torque is excessive. Power down any electrical equipment before fastening or removing screws inside panels or enclosures.