Vtg C-Thru Ruler Co Proportional Scale Circular Slide Rule PS 80 Round USA

Vtg C-Thru Ruler Co Proportional Scale Circular Slide Rule PS 69 5" Round USA

Vintage C-Thru Ruler PS 80 Proportional Scale Dial Tool

The C-Thru Ruler Co. 15 inch Folding Parallel Rule. Made in USA

Artist Drawing Tool Proportional Scale Divider Ruler Craft Drafting And Image**

Folding Parallel Rule C-Thru Ruler Company 1500 - 12 inches in Box

Rapid Rule Aluminum Rotating Scale Ruler engineering & Vtg Alvin Triangular

Vintage 6" Dietzgen Excello Drafting Scale Ruler Rule w/Leather Case #1556 USA