Vintage 1928 Keystone Solid Copper Adjustable Parallel Rule Bevel Protractor

Vintage 1928 Keystone Solid Copper Adjustable Parallel Rule Bevel Protractor

Vintage 1928 Keystone Solid Copper Adjustable Parallel Rule & Bevel Protractor

Up for sale is a rare vintage 1928 Keystone adjustable folding parallel rule and protractor layout gauge, crafted from solid copper.

Markings & Details:

• Patent: Stamped "U.S. PAT. 1690882" (Patented Nov. 1928)

• Origin Stamps: Stamped "ST. PAUL, MINN. MADE IN U.S.A." on the protractor dial disc and "KEYSTONE ADJ. CORP. / PITTSBURGH, PA." on the reverse hub.

• Features: Features $0^\circ–360^\circ$ angle graduations around the center pivot wheel, ruler graduations along the arms, and precision pinholes for drafting arcs or scribing parallel lines.

Condition:

Solid vintage working condition. Center pivot joint turns and holds angle positions properly. Displays a rich, authentic natural copper age patina with light shop wear as pictured. Measures ~4.5" long when folded.

Please review all high-resolution photos for exact cosmetic condition. Ships securely packaged. Selling as pictured 090526 gp