1066 snapping 540 shafts

Will be curious to hear any thoughts, pro or con.

Had a 1066 now for maybe 8-10 months. Bought at same time, a Terrain King 15' flexwing HYDRAULICALLY powered mower. Runs off the 540 shaft. No shafts to the mower at all, 100% hydraulic.

Hanging on the 540 shaft is a 'speed increaser' that takes the 540 shaft and multiplies it by 4x to 2,160 rpm's and then the hydraulic pump is attached to the multipler.

First shaft broke within 1-2 hours of "putting around the farm", I really wasn't "working" on cutting things. I chalked it up to being 40 years old and working hard again.

Put new shaft in (pain to do!) and got maybe 100 acres cut... snapped again.

Had an engineer friend over, looked at the shaft. He said in his opinion, I was running it too slow (I sometimes cut roadside and DO dial down RPM's to create less havoc)

He said that was the problem.... since the multipler was doing 4x, the torque on the shaft was greatly increased. The way to lower that increased torque was to maintain it at full speed. (keeping the momentum going)

He concluded by saying if I adopted the logic of "when the mower is working, I'm running no less than 540 shaft speed"

The momentum of having it at speed is easier on it than running it at slower speed.


What say you?

Keeping the shaft at 540 will reduce the torque on the shaft. If we assume the mower needs constant power to cut grass, and power = torque * shaft speed, increasing the shaft speed will decrease the torque
required. You said the speed increaser "hangs" on the end of the PTO shaft. If it really puts a lot of weight on the shaft itself, it my cause the shaft to break from fatigue.

I agree. I would make sure the pump/overdrive was supported well. The reason tractors keep the gear speed in the trans close to the clutch is to keep forces on the teeth low because they are whizzing. Use reduction first, and everything must be stout. Jim

(quoted from post at 17:26:53 07/01/19) Keeping the shaft at 540 will reduce the torque on the shaft. If we assume the mower needs constant power to cut grass, and power = torque * shaft speed, increasing the shaft speed will decrease the torque
required. You said the speed increaser "hangs" on the end of the PTO shaft. If it really puts a lot of weight on the shaft itself, it my cause the shaft to break from fatigue.

Click to expand...

I did use the phrae 'hangs" on the end of the shaft... probably bad wording.

I had a bracket fabricated that fits over entire end face of pto. There is a hole that lets the 1000 shaft come through (somthing like 4" so the lip on pto helps keep bracket in place.

Then of course, a smaller hole for the 540 to protrude. The increaser is then bolted to this braciet (which I think is 1/2" steel but never measured)

Regarding pto speed.... I never realized I was putting more stress on things running at lower speeds. As I think through it, it makes some sense.

If there is any misalignment from a ridgid bracket to the shaft it will work harden and fail. Look at the break in the shaft. If it looks swirrly and clean, it is likely twisted. If it is granular over much of it, andonly slightly swirly, it could be the alignment. When it is assembled, and before putting the bolts in the increaser, hold it in place and look for a wedge shape gap indicating a misalignment. Jim

You should have a double roller chain
coupler, Love Joy or other flexible
coupler between the PTO and pump. Double
roller chain is probably better suited for
the high torque.

Karl f

(quoted from post at 10:53:30 07/03/19) You should have a double roller chain
coupler, Love Joy or other flexible
coupler between the PTO and pump. Double
roller chain is probably better suited for
the high torque.

Karl f

Click to expand...

To be clear and exact, there IS something between the PTO and the pump.... the speed increaser. It's hard mounted. How would one use a double chain or something else?

(never heard of a Love Joy....will google it)

if the bracket is not square to the pto shaft or not centred within a few thou you will have problems
how did you check the bracket to pto dimensions

can we see some pics?

What is horsepower of 1066? 540 only good
for 75 to 100, closer to 75.

(quoted from post at 09:21:09 07/04/19) What is horsepower of 1066? 540 only good
for 75 to 100, closer to 75.

Click to expand...

I'm not an expert on these things but I think the claimed HP at the PTO is 125 (as per Tractordata)

I can't imagine they'd build a 125 HP pto and slap a 75 hp limited shaft in it???

Here's a couple pictures (if I can figure out how!)




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I don't have a top-link on this thing so the top-link mount plate is available to me.

I might take something (chain, cable ??) and attach it to the mount plate and take it down to the engine hoist tab that's bolted onto the speed increaser.

Put a turnbuckle or something in between so I can tighten it up a bit....logic being to (try) to move some of the weight off the mounts and take it up to the top-link mount plate.

Right now, just mulling that over in my head, not sure how to put the parts together or what I'd need.

Decided if this snaps again I might look into converting multipler into 1000 shaft size and mount it there however, since they stopped making it 20/30 (don't know) years ago, they might not have the idler gear & input gear that I'd need so it might be impossible.

Followup thought is to get different mower however, I saw it working fine prior to buying it....indeed, I USED it prior to buying it so I have to think it's a mating issue of some form (or as suggested to me, a torque problem therefore I need to keep it maxed at 540 rpm's, something I was NOT consistent with)

I had no idea running it slower would increase the torque on the shaft.

Not a cheap (but not 'expensive') lesson to learn however, it was a HEAVY lesson to learn!!

torque is why they made 1000 pto. I was wondering why you were using 540 myself? is that mower using all the power the 1066 has? if so I would go 1000 shaft.you will get less twisting effect ( TORQUE) on that shaft
540 high hp eat gearboxes and PTO shafts often

(quoted from post at 13:57:24 07/04/19) torque is why they made 1000 pto. I was wondering why you were using 540 myself? is that mower using all the power the 1066 has? if so I would go 1000 shaft.you will get less twisting effect ( TORQUE) on that shaft
540 high hp eat gearboxes and PTO shafts often

Click to expand...

Now in hindsight, I'm beginning to conclude the first one that snapped was snapped by use, not a pending failure (though I'll never know that for sure)

Reason I'm using 540 is.... the speed increaser is setup for the 540, plain & simple. If it was set for the 1000, I'd be using the 1000.

When I got it, I didn't think about these issues cropping up (I don't have that kind of experience with tractors) Since it was on a Deere (if that matters) working FINE, I had no reason to think it wouldn't work fine on an International.... Though his Deere had something like 80 hp and this is something like 120 (?)

I called Alamo once about the increaser.... my take away from that conversation is I'm "stuck" with what I have.... I have since acquired a manual and in there, it appears that at one time, they offered a 1000 compatible kit for it. Given the age of mower, I'm doubtful those are still available however, I intend to call them tomorrow or next week to find out.

Still.... if it were to go on the 1000 shaft, the way it hangs, it would conflict with the 540 shaft. I'd almost need to eliminate the 540 to make the 1000 work. (maybe I could angle it and have it work but I really detest that idea, causes hose getting in the way of tire issues)

(quoted from post at 05:30:01 07/04/19)

To be clear and exact, there IS something between the PTO and the pump.... the speed increaser. It's hard mounted. How would one use a double chain or something else?

(never heard of a Love Joy....will google it)

Click to expand...

Sorry I mis understood the details. I believe there should be something flexible to compensate for slight mis alignment of components. My limited experience with haybines and a mounted brush cutter, have a flex point at the PTO. The hydraulic pump on the haybine only has a stop arm against the drawbar which allows the pump mounted assembly to float while holding the pump stationary. The brush cutter has a solid mounted pump to the tractor PTO similar to your pics, but has the flexible chain coupler to allow for alignment issues.

You would need to change some aspect of your mount to allow for flex.

https://images.app.goo.gl/UiqTJLEj9zEq396fA
Double rollerchain coupler

https://images.app.goo.gl/FYhSAh45Lm6yDBRdA
Pump solid mounted with chain coupler

I can't find a pic of the haybine type hooked up, sorry

Karl f