Farmall 130 PTO question

[Ron Thomas]

I have a 3 point hitch on the tractor and want to use a 3 point rotary cutter to mow my fields. The PTO is 9 inches off-center. Can I use a cutter like a Woods 48" Brush Bull with that degree of PTO offset?

[Matt Kirsch]

Short answer: No. You'll tear up the universal joints after about 15 minutes.

[George Willer]

A little longer answer... As long as the tractor shaft and the mower shafts are parallel and in phase it will be fine. That's what universal joints do if they're correctly timed. The joints are under a lot of strain in a turn, however when the shafts are no longer parallel. They'll tell you when you turn too short. I'd hitch farther left on the drawbar so the left side of the mower and tractor line up.

Another potential problem to be on the lookout for... pulling the shaft halves apart in a right turn.

[Merlin]

George, I'm not quite following your explanation. I don't have a bush hog, but my neighbor does, but no tractor. I have a 3 point hitch on my Super A and he uses my tractor and his bush hog 3 or 4 times a year. I've never really looked at the set up very close, but there are 2 U joints on the bush hog. When he gets it hooked up, there is no way the U joints can come loose. There is no drawbar on my tractor, just top link, lift arms, and a anti sway bar. The bush hog could be considered "ridged" as far as left or right movement is concerned. He has one swivel wheel in the rear, so when he turns, the bush hog just follows along.

[George Willer]

George, I'm not quite following your explanation. I don't have a bush hog, but my neighbor does, but no tractor. I have a 3 point hitch on my Super A and he uses my tractor and his bush hog 3 or 4 times a year. I've never really looked at the set up very close, but there are 2 U joints on the bush hog. When he gets it hooked up, there is no way the U joints can come loose. There is no drawbar on my tractor, just top link, lift arms, and a anti sway bar. The bush hog could be considered "ridged" as far as left or right movement is concerned. He has one swivel wheel in the rear, so when he turns, the bush hog just follows along.

Merlin,

OK, I'll explain it as well as I can. Your setup doesn't put the U-joints under stress in turns like a true trailer mower does. It's still very important for the joints to be in phase.

Most PTO shafts are made with two square shafts that telescope together. There's a 50/50 chance of timing them correctly when you slide the two halves together unless you know how to do it correctly.

The individual joint's very nature is to turn the shaft at a different speed from the input shaft. The speed is constantly changing 4 cycles per revolution. Here's the fortunate part... If the joints are in phase, one joint makes the opposite correction to the speed so they cancel each other.

To be in phase, the two yokes connected to the two ends of the main shaft MUST lie in the same plane. Simple if you know how to do it.

If the shaft isn't timed correctly, either the engine or the implement, or both, have to run "lumpy", putting everything under unnecessary stress.

With a trailer implement the two yokes go out of phase in a turn, since they are no longer parallel. In a tight turn you will notice pronounced knocking.

[Merlin]

Thanks George. I've just never given it any thought before.

[Ron Thomas]

George:
Thanks for the reply. I too have a 3 point hitch on my 130, and the mower I'm looking at would be mounted in the manner Merlin referred to.

Merlin: is the PTO on your A offset like my 130? If so, does your friend have any problems with the PTO when he bushhogs?


Ron Thomas

[Matt Kirsch]

Ron,

The A, Super A, 100, 130, and 140 are all basically the same exact tractor underneath, with improvements and refinements added along the way. They all have offset PTO.

That basic tractor design was in production from 1939 through 1976. IH made a limited number of "274 Offset" tractors between 1977 and 1981, which may or may not share the same chassis, but the layout was basically the same.

[Merlin]

George:
Thanks for the reply. I too have a 3 point hitch on my 130, and the mower I'm looking at would be mounted in the manner Merlin referred to.

Merlin: is the PTO on your A offset like my 130? If so, does your friend have any problems with the PTO when he bushhogs?


Ron Thomas

Matt explained it very well. I'm not sure how he has it set up with the U joints, but he doesn't have a problem. He just comes and gets the tractor, goes home and backs up to it and hooks it up and start cutting. I've never had a use for a bush hog so I just don't pay any attention to them.