Disston Tractor Tank

The Disston Tractor Tank, also called the Six-Ton Tractor Tank, was an American light tank of the mid 1930s. It did not meet the market's expectations, being a fairly primitive design, but its low production price was favored.
Development.
The tank was created as a joint venture by the Caterpillar Corporation and the Disston Saw Works. Caterpillar provided the chassis, which was from a standard Caterpillar Model 35 civilian tractor, and Disston provided the tank body, which was bolted on to the Caterpillar chassis. The Caterpillar track was lengthened by adding a road wheel to the front of the track assembly, but some examples apparently do not have this lengthened track.
The Disston had a 37mm gun mounted in the body, and a turret with a .30 caliber (7.62 mm) light machine gun. It weighed about six tons, probably had a speed of 5 to 6.5 miles per hour, and had armor sufficient to stop small arms fire. The crew consisted of three men. At a cost of $21,000 (), the Disston was cheaper than similarly-armed tanks, but – being quite slow, with tracks unsuited for difficult terrain, thin armor, a high boxy superstructure, and the engine exposed in the front – was generally deemed unsatisfactory even so.
Operational history.
A few were sold and delivered to Afghanistan and entered service there. Some of these units still exist, in broken-down condition or in Afghan scrapyards. The vehicle was marketed to Kuwait and Romania, and perhaps some other countries, but there is no reliable evidence that any were sold.