Value Collection BDNA-MP30579-2 Hex Cap Screw 1/4-20 X 4 in

Product Description

The VALUE COLLECTION BDNA-MP30579-2 is a partially threaded hex head cap screw designed for fastening applications that require corrosion resistance and dimensional precision. Sized at 1/4-20 UNC with a 4-inch length under head, this fastener is manufactured from Grade 316 stainless steel and left uncoated, making it well suited for wet, chemical, or marine environments where standard carbon steel would corrode prematurely. The hex drive head accepts standard hex wrenches and sockets. Installation is straightforward for any mechanical or industrial trade professional who works with stainless fasteners in demanding service conditions.

This cap screw is used in plumbing, HVAC, pool equipment, and general mechanical assembly where a 1/4-20 UNC partially threaded fastener is specified. The partial threading provides a smooth shank section under the head, which helps locate mating components and reduces stress concentration in the shank. It is appropriate for both indoor and outdoor installations where stainless steel material is required by specification or environmental exposure demands it.

Key Features

• Grade 316 stainless steel construction for superior corrosion resistance in chloride and marine environments
• 1/4-20 UNC thread form for broad compatibility with standard inch-series tapped holes
• 4-inch length under head accommodates thicker assemblies or applications requiring extended grip length
• Partially threaded shank provides a bearing surface and aids in component alignment
• Uncoated finish eliminates concerns about coating adhesion, flaking, or chemical incompatibility

Compatibility

Designed as an OEM-style replacement or general-use fastener for any assembly specifying a 1/4-20 UNC hex head cap screw in 316 stainless steel with a 4-inch length under head.

Installation Notes

Installation is typically performed by a licensed mechanic, plumber, electrician, or HVAC technician depending on the assembly. Ensure the tapped hole thread form matches 1/4-20 UNC before installation. Applying an anti-seize compound rated for stainless steel is recommended to prevent galling, which is a common failure mode when threading stainless fasteners into stainless tapped holes. Do not overtighten, as Grade 316 stainless has lower tensile strength than alloy steel fasteners of the same size.