Aeronautical Instruments & Tools
Stock No. 4468
Price = n/a
Sold
Air Ministry Hasler Revolution, Circumference and Cutting Speed Indicator - Click for the bigger picture

Air Ministry Hasler Revolution, Circumference and Cutting Speed Indicator

These instruments were produced by the Hasler Telegraph Works and first marketed in April 1915. This example is Air Ministry (AM) marked with King's Crown and would have been used in RFC and RAF workshops to check the rotation speed of lathes and engines up to 10, 000 rpm. The instrument is Swiss made and comes in a velvet lined fitted case. The patent mark on the backplate indicates a date of 1914. When new the retail price was a massive £6.00! A wonderful instrument dating to the very early days of aviation. Sold as a collectable. Case diameter 2.75" (7cm)