I made some posts last year about making a garden tractor from old car parts, but that was before we had the Steemmakers community. This is the first repost in a series about making a small tractor from old car parts found in the junkyard. Follow me to see the rest of the story including some videos of the tractor in action.
In the spring of 2006 I found an old article from Mechanics Illustrated that described a garden tractor made from old car parts. A homemade garden tractor what a fantastic idea! I had just gotten an oxy/acetylene torch kit for Christmas and was looking for a project. Our garden is pretty big and we don't own a tiller, so I was thinking about getting a garden tractor for plowing, disking, and cultivating. Our town has a great junkyard, so car parts would be easy to find. Perfect. I spent hours studying the plans, but since they are only eleven pages long, that meant that I was laying in bed every night staring at the drawing above, thinking about how I was going to make every part. My wife started to think I had lost my mind. When I spent the next three weekends in the junkyard, she knew I had lost my mind because I came back every day with an ear-to-ear grin.
The article, by S. S. Miner, was originally published in 1960. I found the homemade tractor plans at VintageProjects.com where you can also find out how to turn a fish head into an ashtray. (Seriously - a fish head ashtray.)
After bringing home a transmission and axle from a Mitsubishi pickup, 900 pounds of angle iron, and a 9 HP Briggs & Stratton engine, it became clear that some parts of the plans were not going to work. The contents of your typical junkyard were a lot different back in 1960, so the plans called for components from cars built in the '30s, '40s, and '50s that I couldn't get. The 1985 Mighty Max that provided the major drive components for my project is as common as dirt, but it is a much bigger car than the 1938 Ford parts in the plans. My modern 5-speed transmission is roughly twice as long as an old 3-speed and the differential housing is wider too.
Harvesting the transmission and axle was a scary experience. Our town's junkyard is about 20 acres of cars, piles of scrap metal, and all kinds of stuff. The people who work there are all driving around in big machines and most of the time they are near the front of the yard where they sort cans and other scrap. The truck I wanted to get parts from was way back in a secluded part of the yard. If something went wrong they wouldn't even hear a scream.
I picked out the transmission and negotiated a price with the junkyard's owner. (That is the cheap way to do it. If you pull the part and bring it to him, then start negotiating the price it will cost twice as much.) He sent out two guys on a front end loader to "help" me. They picked up the truck and set it down on the passenger side so that the drivers side was straight up in the air. The truck was teetering back and forth, so they picked it up again and shoved some old tires underneath to stabilize it a little. When the guys and the loader left I was on my own -- not a good feeling.
The extraction went off without a hitch, though, and I ended up with a transmission, axle, drive shaft, steering gear, and a cool steering wheel from a Caterpillar loader.
Unfortunately, the transmission turned out to be the reason this particular Mighty Max was in the junkyard. One of the teeth on the reverse gear had chipped, not enough to ruin the gear, but the chip found the nearest bearing, got wedged in, and scrambled it. I had to buy a book about transmissions to help me get it apart, but after that it was easy to find a replacement bearing, press it in, and reassemble. Along the way I learned how transmissions work, which is fascinating.
The size of the available car parts was not the only problem. Older cars used to have a torque tube that would transfer the thrust from the rear axle to the transmission. The drive shaft ran inside the tube, completely enclosed. Miner used the outer torque tube as a place to mount the seat of his tractor and didn't have to worry about protecting the operator from the spinning drive shaft. A modern drive system uses a 3" diameter driveshaft that has flexible couplings at each end and the axle's thrust is transmitted through the suspension.
Rather than attempt to adjust the plans during the building, I bought myself a copy of DeltaCAD and set to work redrawing the tractor plans. I don't have a lot of experience with CAD programs, but DeltaCAD works well for me. After using the free version for a while it was clear that the $40 price tag was worth it. Of course, the danger of starting a little redesign is that pretty soon everything looks like it needs an update you end up doing a big redesign.
Stay tuned for more . . .