Spi 13-191-2 Double Square Rule 4 Inch 4R

Product Description

The SPI 13-191-2 is a 4R double square rule with a 4-inch hardened steel blade, designed for precision layout and inspection work in machining, fabrication, and toolroom environments. The 4R graduation style provides four incremental scales on a single blade: 1/64 inch, 1/32 inch, 1/16 inch, and 1/8 inch. Hardened steel construction resists wear and maintains accuracy through repeated use in demanding shop conditions. This rule is a standard layout tool for machinists, tool and die makers, and fabricators who require reliable, fine-increment measurement on a compact blade.

The 13-191-2 is suited for precision measurement tasks in machine shops, toolrooms, and fabrication facilities. Its compact 4-inch blade length makes it practical for close-tolerance work in confined areas, part inspection, and scribing layouts. The 4R graduation style is a widely recognized standard among machinists and metrology professionals for its multi-scale readability on a single blade face.

Key Features

• 4-inch blade length for compact, close-tolerance measurement
• 4R graduation style with four scales: 1/64 in, 1/32 in, 1/16 in, and 1/8 in
• Hardened steel blade for durability and long-term accuracy
• Single-unit packaging suitable for individual toolroom and bench use

Compatibility

Designed as an OEM-style replacement or direct addition to standard double square sets used in machining and toolroom measurement applications.

Installation Notes

No installation is required for this hand measurement tool. Handle with care to avoid nicking the blade edges, which can affect measurement accuracy. Store in a protective case or sleeve when not in use to prevent damage to the graduated markings. Periodic cleaning with a lint-free cloth and light machine oil will help maintain blade condition.