Wm. B. Osborne's final version of the Osborne Fire-Finder came in 1934. Only the sighting mechanism changed from the 1917 model.

He had invented a camera that could now take high-definition panoramic photos of the entire seen area from every lookout. There was no longer a need for the complicated front sight, so it was replaced with a simple set of cross hairs. The rear sight became brass, with a peep sight and a vertical angle scale graduated in 1/10th degree increments below or above the reporting lookout elevation. An improved azimuth scale, calibrated to 1/60th of a degree, gave the firewatcher an instrument with accuracy equal to that of a surveyor's transit.

The newer 1934 sight ring assembly easily interchanged with the 1917 model, making it a minor transition at a minimal cost.

Leupold-Volpel in Portland became Leupold & Stevens Inc. in 1942 and continued to be the principal manufacturer until 1992 of what is now known as the Osborne Fire-Finder #4. After World War II, the weight was reduced by half, as the main body assembly was made of aluminum alloy instead of cast iron.

More than 3,000 Osborne firefinders, the most well known of many different fire locator alidades, eventually found their way to mountaintop lookouts all over the world; from New England, to New Zealand. Some have even been modified with a high-power (10x) Leupold rifle scope capable of precisely pinpointing a single snag afire 20 miles away! You can buy one new from a California manufacturer, the Palmquist Tool Co., for $4,000.00.

Ray & Osborne firefinder
1934 Osborne rear sight	1934 Osborne front sight
1934 Osborne parts list - top view
1934 Osborne parts - side view