A simple tractor model, built as a warm-up to try my hand at working with a miniature construction set. The front axle is steerable with a steering wheel, and the rear wheels are doubled up on half axles.

  The little tractor isn't particularly complex, but a few problems did crop up. The engine compartment is only eighteen millimetres wide, making access rather tricky. I had to take it apart twice because of "one screw". In the last photo, there's a tractor wheel from a classic Meccano set for scale comparison.
  Also, note the screws are not gold-plated yet, simply model No1.