Vintage Opisometer Rolling Inch Counter and Drafting Tool
The inch counter is used for exact measuring of distances on maps of all classes, nautical, charts, engineering, plans, drawings, and blueprints. The counting disc projecting over the edge of the casing indicates on one side the traced distance in feet and on the other the number of full revolutions of the pointer; it serves also for instant reset*of the pointer to zero. This instrument is indispensable to hikers, motorists, airmen, architects, surveyors, technical offices, schools etc.
INSTRUCTIONS FOR USE
Set the pointer and the counting disk to 0 by turning thellatter with your thumb.
The fine adjustment of the pointer is attained by means of the tracer wheel.
While holding the instrument in the vertical position, nove the tracer wheel along the line to be measured. The pointer will indicate on the dial the exact distance traced. In case of long distances, the counting disk shows the footage traced and the number of full revolutions of the pointer.
Actual product colour may vary due to photographic lighting sources or your monitor