Decide the model of the future tractor and make the necessary drawings. Examples of such technical creativity here: http://www.pan-as.ru/load/samodelnye_traktora_chertezhi/10-1-0-868 and here: http://samodelniy.ru/kak-sdelat-traktor. On these sites you will see drawings of the major parts and appearance of the resulting design.
Pick up the necessary parts and tools. By construction, mechanics Simonov, the gearbox can be taken from the truck GAS-53, the clutch mechanism from the car GAS-52. The front wheels of this design were taken from the GAZ-69, other details – various models of cars. Decide what is available to you and gather all the main parts.
Proceed to the manufacture of the frame. Welded symmetrical frame can be made from stock metal. In particular, Simonov used the channel No. 10 channel No. 12 channel No. 16 and a metal pipe to make two side members and a cross member. The frame of the cab floor can be welded of a tube with a rectangular cross-section 60x40 mm. Assemble the chassis of the tractor on the frame: install the power unit, transmission front and rear axle with wheels. As the power unit it is possible to use a diesel engine, for example, with the Bulgarian loader.
Attach the engine to the clutch basket and plug the transmission. Note that when connecting components of different types of machines will certainly have to make any design improvements. It all depends on attention to detail and your ability. Examples of Assembly of the chassis of a homemade tractor: http://mini-traktor.masteraero.ru/minitraktor-4.php.
Decide on the type of steering. Simonov offers to make it hydraulic as it works only when the engine and much easier to use than mechanical. Insert the glass in the cockpit, attach the door, which can be taken from another tractor. Equip the wiring using the diagram, for example, from the tractor T-40. Complement the instrument panel, install lights and signal lights.
Remember that homemade design must pass a state inspection and to obtain a registration number. Without that to start working not.