UNUSUAL BROWN & SHARPE NO. 510 DRAFTING PROTRACTOR

Stamped 'Brown & Sharpe Mfg. Co. Providence, R.I. U.S.A.' along with '510' beside the B & S logo. Some minor oxidization on one side. Uncleaned as found.

Patent information can be found via datamp.org and the National Museum of American History wrote extensively about this item in their collection.