Adjustable 300 mm Construction Square Irwin 10503547 — angle measuring and marking tool

Adjustable 300 mm Construction Square Irwin 10503547 — angle measuring and marking tool is a metal layout square with a 300 mm blade and an adjustable head that allows precise setting and transferring of angles. Designed for carpenters, framers and general construction professionals, the tool delivers accurate 90° layouts and variable-angle measurements. Its durable metal construction and clear engraved scale support repeatable marking, measurement and on-site adjustments for cutting, joinery and framing tasks.

Advantages

The adjustable head enables quick locking to common and non-standard angles, reducing time spent on repeated setups. A clear, easy-to-read scale is engraved on the blade to maintain visibility under workshop and site conditions. Robust metal construction resists wear from regular use while maintaining straightness and reliable reference lines. The compact 300 mm size combines portability with sufficient length for most carpentry and trimming operations.

Suitable for

• Carpentry layout and marking
• Framing and trim work
• Transferring and setting angles for cutting
• Measuring and marking joinery
• On-site measurements and quick checks

Key specifications

• Blade length: 300 mm
• Material: metal construction for blade and head
• Adjustable head for variable angle setting and locking
• Engraved measurement scale for repeatable marking
• Compact design for portability and workshop use

How to use

Position the blade against a reference edge and loosen the adjustable head to set the required angle. Align the head to the desired angle using the engraved scale or by matching to an existing angle, then tighten the head to lock the position. Use the blade as a straightedge to scribe lines or mark points directly onto the workpiece. For 90° layouts, set the head at the right angle and verify alignment before marking. Store the square flat or hung to protect the blade from bending.

Usage recommendations

Keep the engraved scale clean and free of debris to ensure clear readings. Periodically check the head locking mechanism for tightness to maintain angle accuracy, and avoid dropping the square or exposing it to heavy impacts that could deform the blade or head.