Vintage antique large draughtsmans architect T-square made from mahogany and ebony (1940s)

Vintage Large  draughtsmans Architect T-square antique made from mahogany and ebony wood from the mid-20th century (1940s). A lovely piece, and in great condition, with not too much wear. Has the original brass screws and the chamfered ebony wood edge is still intact. Has the makers mark on a small brass plate reading: R. L. Esson & Co. Ltd. Johannesburg, a renowned maker of precision instruments. This is a fascinating vintage draughtsman's t-square with superior quality and generously sized for the larger project. R. L. ESSON & CO. Ltd. Southern Life Buildings, cor. Main and Harrison Streets, Johannesburg, were manufacturers and suppliers of drawing office materials. They operated between the 1920s and 1950s.