Ground Driven PTOs
Ground Driven PTOs

Ground Driven PTOs

by Khoke and Ida Livingston of Davis City, IA

One of the ways tractors both gained and maintained their appeal is from the wider range of machinery they can power with the PTOs they carry. This definitely gave them the advantage over draft power. But is it going to stay that way? It may not have to be on a small farm.

During the horsepower road trip Khoke and I went on a couple years ago, we got to see some examples from folks who knew which side of the fence they were on. We saw a number of machines that were reworked and reinvented to make them run off the power source of their choice, namely horsepower.

Ground Driven PTOs
An Allis Chalmers tractor converted to a forecart. Note the PTO shaft on the backside.

Delano’s Horse Powered Allis Chalmers

The Smokey Mountains rise abruptly out of a plain only a couple miles east of the folks in the Delano community. These folks wanted to grow some grain in their relatively flat (for Tennessee) fields. A threshing machine takes a lot of power, and since it runs for grain in the hottest days of summer, it can be hard on horses to generate the power needed in southern Tennessee’s unforgiving heat.

Setting aside the issue of heat and the horses, one also has the shirt drenching humidity to contend with. One can ignore personal comfort for the greater goal, but when the shocked grain never actually dries out because of humidity, it will either mold or sprout, or both. This is as undesirable as we might imagine.

So when the Delano folks came across the smallest grain harvester they had ever seen, they didn’t hesitate to buy it. This harvester was a precursor to the combine and was made to be pulled behind a tractor. Now all they had to do was figure out how to power it with horses.

Ground Driven PTOs
Ammon Weeks looking over the pull-behind combine in the Delano, Tennessee community.

I believe that there are now ground driven PTO forecarts available that one could buy. There was one demonstrated at the Cedar Creek Plow Days in Linden, Tennessee this past October; it was pulling and powering a square baler. James and Norman Martin, a father and son living in Delano, Tennessee, made their own ground driven PTO forecart.

Starting with an old Allis Chalmers tractor, the engine and front wheels were replaced with a tongue. Horsepower to be replaced with horse power. Now, instead of the engine powering the gears that activated the wheels and PTO, the wheels did it. This reversal shouldn’t be too hard to understand by anyone who has ever had a tractor or truck with a bad starter and used a hill or some other way of getting the wheels going to help start the engine. Only this isn’t engaging an engine, it is simply activating the gears so they are engaged and working.

Now with the power source reversed and coming from the wheels instead of the engine, the gearshifter works in reverse order. This means that 1st gear is now road gear and 4th (or whatever the highest gear is) now is 1st. A couple issues ago I wrote about Hoover Feed Mill that used a factory winch gearbox to make a horsepower unit. It originally had a motor that ran at a high rpm and geared down to turn the winch slowly to pull incredible weight with much torque. This was reversed on the horsepower with the horses powering the slow end and the high rpm machinery running on the other end of the gear box where the motor had been. This reversal on the tractor reverses the order and function of the gears.

Does it really work as well as a tractor? Without thinking about the turning radius, it should. But without a side by side test one cannot be sure. The two main considerations are whether you can keep the wheels turning and on the ground. Torque and traction. Torque; do you have enough horses pulling it? Traction is all about having enough weight to keep the wheels on the ground and turning. Heavy metal wheels with deep cleats would help.

Ground Driven PTOs

The Brubakers Ground Driven PTO Combine

In Hillsboro, Ohio, John Brubaker took a pull-behind combine that looked very similar to the one in Delano, only it was a larger model (AC 60). Instead of creating a ground driven PTO forecart of some kind to drive it, he rearranged the gears on the machine itself to be ground driven.

John took off the right wheel and replaced it with a ground driven bull wheel. This wheel was heavy with deep cleats. Then he took a Massey Ferguson baler gearbox and where it once had the baler crank arm attached, he bolted to the bull wheel. This union redirects the power source for the combine.

Ground Driven PTOs

On the other side of the Massey Ferguson baler, John extended the shaft out to run a chain and sprocket assembly. This chain and sprocket assembly runs the PTO shaft that originally engaged the machine. From there the machine is running because the bull wheel is now powering the PTO shaft.

John made a seemingly minor adjustment that actually made a significant difference in the combine’s ease of use. This was by replacing the original 2-inch wide variable speed belt on the cylinder drive pulley with a thin “B” v-belt. The thinner belt takes considerably less power to engage the cylinder. The cylinder takes 90% of the power. The 2-inch wide belt was really stiff.

Ground Driven PTOs

This combine is used throughout the summer in his community to harvest oats, spelt, einkorn, and wheat. Oats take the most power to thresh as the heads vary so much in height that you have to cut lower and run a lot of straw through it.

On small plots of grain this AC 60 combine can be pulled with 4 horses. But if doing any kind of larger field it takes 6 horses. These horses are driven in tandem so that none of the standing grain is walked on.

More Ground Driven Forecart Types

One of the families living in the Winchester community near Hillsboro Ohio also have a Allis Chalmers B tractor rear end converted into a ground driven forecart like the one in Delano. They used this to power their 5ft brush hog. John has a brush hog that he uses too, only his ground driven forecart is made from a truck rear axle and transmission. He set this up by shortening one side of the drive axle and its housing until the wheels matched the 5ft brush hog. Then a roller chain is used to engage the transmission which is sitting on top of the axle. This chain reaches down to connect to the rear facing PTO. Now the PTO can run whatever it needs to.

Make It

Farming of every kind is steeped with history. Whatever kind of history that appeals to a person, whether by hand, draft or tractor. We look back and appreciate all those who have plowed their furrows through history. But there are those like John Brubaker, James and Norman Martin, among others, who have their faces turned forward to make their own history.