International Harvester W-12 tractor, 1935.
© Science Museum / Science & Society Picture Library
After their 10/30 and 15/30 models, the International Harvester Corporation (IHC) introduced a range of tractor sizes; 12, 14, 20, 30, and 40. The prefix W indicated a standard four-wheeled type, F indicated the Farmall high clearance (usually) three point tractor, I indicated an industrial version, O, an orchard version etc. This tractor is therefore a standard version of the smallest tractor IHC made. The wider range of farm sizes and conditions meant that American manufacturers tended to make tractors in a far greater range of sizes than in Britain. The W series followed the general design principles set out in the 15/30, with some variations depending on size.