Keuffel & Esser Doric All-Plastic Triangular Scale Architect's Ruler 12 Inch

Vintage Keuffel & Esser Engineers Ruler 1420W 10-20-40-50 Scale w Leather Case

Vintage Keuffel & Esser Paragon 1631P Triangular Scale Drafting Ruler

Rare Vtg K&E Keuffel & Esser Co. 18" Drafting Ruler Paragon 1376P-22 Full & Half

Vintage Keuffel & Esser K&E Triangular Architectural Scale Ruler Wood READ

Vintage Keuffel & Esser Co. Paragon Triangular Engineer's Scale Ruler. VGC

Vintage Keuffel & Esser Paragon Drafting Machine Scale Ruler 6" Wood

1947 to 1950 Keuffel & Esser Co NY Wood Architects Triangle Scale Drafting Ruler