Spi 30-393-3 Dial Protractor 6 in Blade Rectangular Head

Product Description

The SPI 30-393-3 is a dial protractor designed for precise angle measurement in fabrication, machining, sheet metal, and general trade work. It features a 6-inch blade and a rectangular head with a 0-90-0 dial range covering a full 180-degree sweep. Dial graduation is 1 degree per increment, with an accuracy rating of 30 minutes of arc. This tool is used by machinists, pipefitters, sheet metal workers, and other trades who need reliable angular reference without relying on digital instrumentation. The blade and rectangular head deliver a stable, repeatable reading on flat stock, pipe, and structural material.

The 30-393-3 is suited for layout and inspection tasks in residential and commercial mechanical work, fabrication shops, and field service. Typical applications include checking miter angles, setting bevel cuts, verifying duct transitions, and confirming structural angles during installation. The rectangular head seats squarely against flat reference surfaces, making it a practical choice for tasks that require consistent repositioning across multiple workpieces.

Key Features

• 6-inch blade length for extended reach on larger workpieces
• Rectangular head for stable seating against flat reference surfaces
• 0-90-0 dial range covering 180 degrees total measurement
• 1-degree dial graduation for clear, direct angle reading
• Accuracy to 30 minutes of arc for reliable layout and inspection work

Compatibility

Designed as a general-purpose dial protractor suitable for use in machining, fabrication, HVAC duct work, and sheet metal layout applications where analog angle measurement is required.

Installation Notes

No installation is required for this handheld measurement tool. Clean reference surfaces before use to ensure accurate seating of the rectangular head. Handle the dial mechanism carefully to avoid impact damage that can affect calibration. Verify zero reading against a known flat surface before beginning layout or inspection work.