March 2018 Green Magazine
So your all-time favorite model of John Deere tractor is the 50 and you would like to have all the different variations—row crop, standard, Hi-Crop. Wait a minute. Deere never built a 50 standard or Hi-Crop, but you are not going to let that stop you.
The standard is easy enough to figure out, just take a row crop and add a standard front axle from some other tractor and some wider tires and big fenders, but what about a Hi-Crop? Now that gets a little more complicated.
Here’s the drive train on a row-crop or standard. Pinions (see arrow)turn final drive gears in opposite direction.
When Deere designed their first Hi-Crop tractors, they could have gone two different ways with their final drives. The first and simplest would have been to fit a sprocket on the end of the axles, which would transmit power to another sprocket on the wheel via roller chain. All enclosed in a housing, of course. Case, Oliver, International, and Minneapolis all chose this solution. Deere chose to not use chains, instead preferring a gear to gear final drive. Install this on the end of a row-crop tractor axle and you now have six speeds in reverse and one forward because, as we all know, when a sprocket turns another sprocket via a chain, they both turn in the same direction, but when a gear turns a gear, they turn in opposite directions. Deere could have solved this problem by putting an idler gear between the two gears in the final drive, but they instead chose to design an entirely new rear axle housing that replaced a gear-to-gear connection with a roller chain.
Here we look into the back of a “G” Hi-Crop. The pinion gears have been replaced by sprockets which, when hooked to the final drives, turn them in the same direction.
Here’s another view of the “G” Hi-Crop. You can see the differential sprocket peeking out from behind the differential. The bottom sprocket is on the end of the drive shaft going to the final drive. The upper sprocket is for the brake.
So now we know why you can’t just machine the axle and housing on a 50 to accept the final drive off a 60 when trying to build your Hi-Crop.
Another view of a “G” rear. Brake shafts and chains have yet to be installed.
Back around the turn of the century, Chris Visser of Fresno, California began to consider the possibility of building a 530 Hi-Crop to fill the gap between the tall 430, 630, and 730s that Deere built. Already realizing all the information laid out in the first few paragraphs of this article, he determined that the final drive from certain Farmall high crops was the best fit and since they were chain drive would move the Deere in the correct direction. Considerable machining had to be done to mount the top of the final drive to the Deere axle housing, not to mention the sprocket, but as luck would have it, the Deere wheels fit on the Farmall axles, only needing a very thin shim for them to fit.
Here’s a Farmall chain final drive installed on a John Deere “B.” Since the tractor has a row crop rear end, if you put a gear final drive on it, the tractor would have six gears in reverse.
Chris built several 530 Hi-Crops but it was Duane Ver Ploeg of Sully, Iowa who expanded the concept to the other tractors of the same family, building several “B,” 50, and 520s, including the ones shown in this article.
Thanks to Chris Visser, Duane Ver Ploeg and Bryan Koskela for providing info and photos for this article.