RAS-120 12" Aluminum Rafter Angle Square

Overview

The Johnson RAS-120 12" Aluminum Rafter Angle Square (RAS-120) is designed for use as a saw guide, stair layout tool, and rafter layout tool in carpentry and framing applications.

Technical Features

• Solid aluminum body construction — provides a rigid, lightweight frame that resists warping and withstands repeated job-site use.
• CNC machined edges — deliver precise, consistent angles critical for accurate cuts and layout work.
• Low-glare, protective powder-coated finish — reduces eye strain in bright conditions while protecting the surface and preserving legibility of graduations over time.
• Permanent graduations and numbers — remain readable throughout the tool's service life, eliminating the risk of markings wearing off during heavy use.
• Scribe notches starting at 1-3/4" — enable accurate transfer of outside increments from the pivot point for consistent scribing tasks.
• Integrated 2x4 board dimension markers at 1-1/2", 3", and 3-1/2" — provide quick reference measurements for standard dimensional lumber, reducing the need for a separate measuring tool.
• Non-adjustable fixed-body design — eliminates the risk of setting drift, maintaining calibration integrity in field conditions.

Applications

• Saw guide — the machined straight edge serves as a reliable guide for crosscuts and angle cuts with a circular saw or hand saw.
• Rafter layout — graduated scale allows accurate marking of common, hip, and valley rafter cuts during roof framing.
• Stair layout — supports accurate marking of stair stringers for consistent rise and run measurements.
• Lumber scribing — scribe notches facilitate transferring measurements directly to standard dimensional lumber for repeatable results.