This design includes two interchangeable heads (a corn head and a rolling reel type head) and an auger that swings from the side of the combine. My kids love to push it and watch the reel roll as they push. When loads are full the auger swings out to dump into a wagon.
Most parts of this combine are to be cut from standard ¾” thick boards no wider than 5 ½”. Patterns to cut the wheels are included, but wheels are sized such that you should be able to find the correct wheel from craft or hobby stores that stock wooden wheels.