Value Collection MSRI0-400120-100BX 4-40 Machine Screw 100-pack

Product Description

The VALUE COLLECTION MSRI0-400120-100BX is a 4-40 UNC machine screw with a round head and slotted drive, sold in a box of 100. Constructed from alloy steel with a zinc-plated finish, this fastener delivers solid corrosion resistance and mechanical strength in light-duty and precision assembly applications. The 4-40 thread designation indicates a No. 4 screw diameter with 40 threads per inch, a common size in electrical panels, instrument enclosures, and small-component assemblies. Length under head measures 0.125 inches. Electricians, electronics technicians, and mechanical assemblers regularly stock this size for panel work and device mounting.

These machine screws are suited for residential and commercial electrical enclosures, control panels, instrumentation hardware, and precision metal fabrication. The slotted drive is compatible with standard flat-blade screwdrivers, and the round head profile sits flush above the mating surface without countersinking. The zinc coating provides a baseline level of corrosion protection appropriate for indoor or sheltered applications. The 100-count box quantity supports job-site stocking and bench-stock replenishment for shops running repetitive assembly work.

Key Features

• 4-40 UNC thread form — 40 threads per inch on a No. 4 diameter shank
• 0.125-inch length under head for tight, low-profile fastening in thin material
• Round head profile — no countersink required
• Slotted drive — compatible with standard flat-blade screwdrivers
• Alloy steel construction with zinc-plated finish for corrosion resistance
• 100-count box for bench stock and repetitive assembly applications

Compatibility

Designed as a standard 4-40 UNC machine screw for use in electrical enclosures, instrument panels, and light mechanical assemblies requiring a No. 4 round-head slotted fastener.

Installation Notes

Installation does not require special tooling beyond a flat-blade screwdriver sized to the slot. De-energize any electrical enclosure or panel before fastening or removing hardware in accordance with NFPA 70E lockout and tagout procedures. Do not over-torque small-diameter machine screws, as the 4-40 thread is susceptible to thread stripping in softer mating materials such as aluminum or plastic. Use a thread-cutting tap to prepare mating holes in sheet metal to ensure proper thread engagement.