Value Collection SFR4-40X3/8 4-40 Flat Head Machine Screw 10pk

Product Description

The VALUE COLLECTION SFR4-40X3/8 is a 4-40 UNC flat head Phillips drive self-sealing machine screw designed for applications where a leak-proof mechanical fastener is required. The screw features a captive silicone O-ring that compresses under the flat head upon installation, creating a seal against fluid or gas intrusion through the fastener hole. Constructed from 18-8 stainless steel with a bright uncoated finish, it provides solid corrosion resistance in moderate-exposure environments. Overall length is 3/8 inches. Sold in a pack of 10.

This screw is suited for light-duty mechanical assemblies, enclosures, and panels where thread sealing is needed without a separate sealant or patch. Common applications include HVAC control panel assemblies, electrical enclosures, instrumentation housings, and plumbing-adjacent components where moisture exposure at fastener penetrations is a concern. The 4-40 thread size and Phillips drive make it compatible with standard hand tools and power drivers. Trade installers including HVAC technicians, electricians, and equipment assembly mechanics will encounter this fastener in production and field-repair settings.

Key Features

• Captive silicone O-ring provides in-place sealing under the flat head without additional sealant
• 18-8 stainless steel construction for corrosion resistance in moderate environments
• 4-40 UNC thread standard for compatibility with common tapped holes in that size
• Flat head profile sits flush or countersunk in mating surface for low-profile installation
• No. 1 Phillips drive works with standard screwdrivers and power-drive bits
• Bright uncoated finish — no plating to chip or flake in service

Compatibility

Designed as an OEM-style replacement or service fastener for any assembly using 4-40 UNC tapped holes requiring a flat head self-sealing screw with a silicone O-ring.

Installation Notes

Installation is performed with a No. 1 Phillips screwdriver or matching power-drive bit. De-energize and depressurize any assembly before replacing fasteners in active systems. Drive to snug contact — do not overtighten, as excess torque will deform the silicone O-ring and compromise the seal. Verify the O-ring is fully seated and undamaged before installation.