VintageStarrett No. 490 Combination Square Protractor Head.
Starrett No. 490 Combination Square Protractor Head. It is a tool used for measuring angles and is part of a combination square set, which typically includes a blade, square head, center head, and protractor head. Key features of the Starrett No. 490 Protractor Head:Material: Made of cast iron or forged and hardened steel. Function: Measures angles from 0 to 180 degrees. Reversible: The blade can be inserted in two orientations, allowing for measurements on both sides of the protractor. Locking Knob: Features a locking knob to secure the blade at a specific angle. Spirit Level: Some models include a spirit level for accurate horizontal measurements. Origin: Manufactured by L.S. Starrett in Athol, Massachusetts. This protractor head is often used in woodworking, metalworking, and other precision layout tasks. It is designed to be accurate and solid, with a focus on quality and precision.