I made these for my son when he was a boy. They are made from 3/4 inch birch. They would make a good Christmas gift for a young male in your family.
Step 1: The tractor
The degree of detail is not for an exact replica, but suitable to stir the imagination of a young boy. Rather than give measurements I included a scale in inches in most of the photos. Begin by drawing the profile of the tractor body. The wheels were turned on my lathe. Axles are from 3/16 inch steel rod with end cap retainers from the hardware store. The exhaust stack is a piece of 1/4 inch welding rod for an oxy-acetylene torch. The steering wheel assembly is from a 3/8 inch carriage bolt with the square portion under the head ground away to make the column round. There will be more on the seat and the gear shift later.