- Joined
- Dec 2, 2015
- Messages
- 24
A good friend of mine has a 1928 McCormick-Deering 10-20 tractor made by the International Harvester Co. He wanted a PTO shaft for it as it did not have one. A PTO shaft was not standard equipment for this tractor, although they were offered. Few farmers needed it (and sure as heck were not going to pay extra for something they did not need!) since PTO powered equipment was still in it's infancy and most stationary machines like the thresher, corn sheller, silage chopper, corn grinder etc., were powered via a flat belt off the tractor's belt pulley. Consequently, original PTO shafts for this tractor are not very common, so I said I would make one for him. On of my 10-20s has a factory PTO shaft so I copied it, but made a couple of changes. The original shaft uses one of those old Bower straight roller bearings, I made the new shaft to use a modern ball bearing. About 8" of the outer end of the original shaft is removable so when you are not using the PTO you can unscrew that part and cover up the hole with the tin cover, so it is not sticking out when you are using the tractor for belt pulley work, (PTO and belt pulley both turn at the same time) To simplify machining a new one, I just made the shaft all one piece.
Before I could make the shaft I had to find a piece of old PTO shaft to give me the splines as I don't have the fixtures and tooling for cutting splines on a shaft. I was looking on my iron racks to see if I could find a piece when a Farmall F20 axle shaft caught my eye, the splined end where the brake drum attaches looked to be about right so I grabbed a female PTO coupling and checked the fit. The splines turned out to be exactly the right size! So I just made the entire PTO shaft out of that F20 axle shaft!
The top shaft in the transmission has a threaded stub that sticks out the rear for the PTO shaft to screw on. I used a 3" long piece of another F20 axle as it was the correct diameter. Then just bored out the center to 1.125" and threaded to 1-1/4" 7tpi left hand threads. This was my first time attempting internal and left hand threads, fortunately I already had an internal threading tool and it was not really any more difficult than right hand external threads. After cutting them to what looked to be the same depth as the original, I took the piece and checked its fit on the tractor. The thread fit was good and it screwed on like it should. I machined the other end of the threaded coupler to be a press fit on the shaft and then welded them together to make it complete.
I could not find a ball bearing with a 3.375" OD, so I used a 35x80 metric bearing and made a sleeve to go over the OD so it would fit in the tractor. I installed the shaft in one of my 10-20s and everything went together and fit like it should so I would say it is a success!
The first picture shows the original PTO shaft on top, new one in the middle and an F20 axle on the bottom. The second is a view of the threaded coupler, old vs. new. And finally, the finished product!
Before I could make the shaft I had to find a piece of old PTO shaft to give me the splines as I don't have the fixtures and tooling for cutting splines on a shaft. I was looking on my iron racks to see if I could find a piece when a Farmall F20 axle shaft caught my eye, the splined end where the brake drum attaches looked to be about right so I grabbed a female PTO coupling and checked the fit. The splines turned out to be exactly the right size! So I just made the entire PTO shaft out of that F20 axle shaft!
The top shaft in the transmission has a threaded stub that sticks out the rear for the PTO shaft to screw on. I used a 3" long piece of another F20 axle as it was the correct diameter. Then just bored out the center to 1.125" and threaded to 1-1/4" 7tpi left hand threads. This was my first time attempting internal and left hand threads, fortunately I already had an internal threading tool and it was not really any more difficult than right hand external threads. After cutting them to what looked to be the same depth as the original, I took the piece and checked its fit on the tractor. The thread fit was good and it screwed on like it should. I machined the other end of the threaded coupler to be a press fit on the shaft and then welded them together to make it complete.
I could not find a ball bearing with a 3.375" OD, so I used a 35x80 metric bearing and made a sleeve to go over the OD so it would fit in the tractor. I installed the shaft in one of my 10-20s and everything went together and fit like it should so I would say it is a success!
The first picture shows the original PTO shaft on top, new one in the middle and an F20 axle on the bottom. The second is a view of the threaded coupler, old vs. new. And finally, the finished product!
Last edited:
