Value Collection 221151PR Shoulder Screw Grade 8 Alloy Steel

Product Description

The VALUE COLLECTION 221151PR is a Grade 8 alloy steel shoulder screw designed for precision fastening applications that require a hardened, close-tolerance shoulder to serve as a bearing surface, pivot point, or locating pin. The shoulder measures 0.5 inches in diameter and 4.5 inches in length, with a 3/8-16 UNC threaded shank. Drive engagement is via a 1/4 inch hex socket. The uncoated finish leaves the alloy steel surface exposed, making it suitable for applications where dimensional precision matters more than corrosion resistance. Machinists, tool and die makers, and maintenance technicians working with jigs, fixtures, or mechanical linkages are the primary installers.

This shoulder screw is used in industrial and manufacturing settings where a hardened shoulder is needed to guide, pivot, or locate a moving component. Common applications include fixture plates, die sets, linkage assemblies, and mechanical stops. The 4.5 inch shoulder length accommodates thicker workpieces or assemblies requiring extended bearing engagement. The 3/8-16 UNC thread provides reliable clamping force once the shoulder is seated fully against the mounting surface.

Key Features

• 0.5 inch shoulder diameter with 0.5000 inch decimal precision for close-tolerance fits
• 4.5 inch shoulder length for extended bearing or pivot engagement
• Grade 8 alloy steel construction for high tensile strength and hardness
• 3/8-16 UNC threaded shank meets ANSI B18.3 and ASME/ANSI B18.3 standards
• 1/4 inch hex socket drive for standard Allen wrench or hex bit installation
• Uncoated finish maintains precise shoulder dimensions without plating buildup

Compatibility

Designed as a standard shoulder screw conforming to ANSI B18.3 and ASME/ANSI B18.3, suitable for use in fixtures, jigs, die sets, and mechanical assemblies requiring a 0.5 inch shoulder diameter and 3/8-16 UNC threaded fastener.

Installation Notes

Installation is performed by machinists or maintenance technicians using a 1/4 inch hex key or hex socket driver. The mating bore should be reamed or drilled to a tolerance that achieves the intended fit class for the 0.5 inch shoulder diameter. Ensure the threaded hole is clean and free of debris before driving the screw. Do not use the threaded shank as a bearing surface — the shoulder is the load-bearing and locating feature of this fastener.