TRACTOR SLUNG PTO SHAFT!!! - PICS.

[JethroB]

Now you are talking extremes, and no that's not what I would do.

I in fact wouldn't put a tool rated for 40hp on a 100 hp tractor in the first place, and anyone who does, shouldn't be surprised of the outcome.

SR

My nephew was doing that with my dad’s (RIP) 40hp equipment. I slowly and gently put an end to that by offering to help him buy his own more suitable stuff. He got the message eventually. And by adding if you borrow anything else I want it back by (X) day.

 

[LouNY]

It is done quite often that the tractor has more power then the attached implement is rated for.
That is why you would set the slip clutch to slip when needed, or if shear bolt protected the shear bolt protects
the implement NOT the tractor.
When I hook up an old sickle bar mower to a tractor the sickle bar mower is only rated for 20 HP.
The tedder only needs around 20-30 when its used the pto powered rotary rake is the same 20-30 hp,
so their protection is to protect the implement.
My brush hog is rated for 80 HP, my new flail mower calls for 65 HP minimum.
The pull type forage harvesters on the farm are rated for 150 - 200 hp so again the implement is protected.

 

[JWR]

It is done quite often that the tractor has more power then the attached implement is rated for.
That is why you would set the slip clutch to slip when needed, or if shear bolt protected the shear bolt protects
the implement NOT the tractor.
When I hook up an old sickle bar mower to a tractor the sickle bar mower is only rated for 20 HP.
The tedder only needs around 20-30 when its used the pto powered rotary rake is the same 20-30 hp,
so their protection is to protect the implement.
My brush hog is rated for 80 HP, my new flail mower calls for 65 HP minimum.
The pull type forage harvesters on the farm are rated for 150 - 200 hp so again the implement is protected.

Yup. Agree. The slip clutch is there to fend off a variety of calamities (one of which is my having to screw with replacing shear bolts.) The slip clutch should be set to slip before breaking gears in the gear box, various parts of the driveline and certainly the driven implement. So long as the slip clutch allows more than adequate torque to the implement and routinely avoids breakage ... things are cool and as they should be. I am rarely, if ever, concerned about tractor HP nor gear box ratings other than when I bought the things.

At risk of prolonging this thread, here are 2 data points in the last 72 hrs:
1) At one property I was using a JD413 small rotary cutter driven by a 24hp Kubota B2150. Hit a hidden root dug up by recent contractor assist clearing a lot. Shear bolt gave way and the U-joint jammed further onto the gearbox output shaft (not flying off in the opposite direction.) It took 45 minutes of lost work time to find a way to dislodge the stuck u-joint from the shaft and get it back in position to replace the aggravating shear bolt.
2) At a different property, driving an 88" very old but sturdy Alamo flail mower with an 81hp MF, the grass is unusually high this year -- heavy tall hay all over the farm even in places usually skimpy. I encountered swamp grass taller and more dense than I ever recall seeing in one of the swampy areas I clear twice a year. The swamp grass wound itself around the rotor and blades of the flail mower to the point of finally freezing the machine. The slip clutch (set just right in my view) worked well -- initially groaning and screaming here and there and then finally halting operation with smoke and some fanfare. No shear bolts thank goodness. But it did take me quite a while to unravel all the swamp grass. Some had wound so tightly around the bearing ends of the rotor the only way to remove it was a sharp old butcher knife. Once cut loose, all is well. The slip clutch always squeaks when the PTO is engaged and my ear is calibrated to expect the right amount of squeak. The spring loaded slip clutch adjustment bolts are stop-nut locked in place.

 

[JWR]

I've said it before on this site, and I'll repeat it here.

You have to adjust the clutch for the hp of YOUR tractor, not to some spec. in a book! That book doesn't know what YOUR tractors hp is.

SR

I disagree. Maybe your comment is clarified via discussion with Fallon but I find that the slip clutch (and shear bolt if so unfortunate as to be stuck with one) is set mainly to keep the torque at the implement down to tolerable levels. Depending on the implement (thinking mostly of various grass and brush cutters) the "incidents" are sometimes simply an overload but more often a sudden shock -- like hitting a post or hidden object of some sort. That sudden shock doesn't relate to the hp of the tractor much at all.

 

[Sawyer Rob]

I disagree. Maybe your comment is clarified via discussion with Fallon but I find that the slip clutch (and shear bolt if so unfortunate as to be stuck with one) is set mainly to keep the torque at the implement down to tolerable levels. Depending on the implement (thinking mostly of various grass and brush cutters) the "incidents" are sometimes simply an overload but more often a sudden shock -- like hitting a post or hidden object of some sort. That sudden shock doesn't relate to the hp of the tractor much at all.

You can think whatever you want but setting a pto clutch for a small pto hp tractor and use it on much of a bigger tractor with heavier loads, like tall thick grass, and the clutch won't last near as long.

Get in heavy grass with the bigger tractor and the clutch will slip a little here and there and wear it out much sooner. Those of us that have been using pto slip clutches for many years, have learned this from experience...

There is a little overlap, but it's a "little" not a lot.

SR

 

[3gunr]

You left off a dollar there Tinhack. $2.25 and $2.30 I would believe...

Before covid i was getting regular gas at my farm in northern mo for 1.19 a gal.

 

[LouNY]

You can think whatever you want but setting a pto clutch for a small pto hp tractor and use it on much of a bigger tractor with heavier loads, like tall thick grass, and the clutch won't last near as long.

Get in heavy grass with the bigger tractor and the clutch will slip a little here and there and wear it out much sooner. Those of us that have been using pto slip clutches for many years, have learned this from experience...

There is a little overlap, but it's a "little" not a lot.

SR

If the mower can handle the HP of the bigger tractor set the slip clutch for the HP the implement can handle.
If the tall grass is requiring more HP then the mower is rated for slow down.
Slip clutches and shear pins are to protect the implement not the tractor.

 

[TexasDigger]

When I was on the farm, when ever we went to use a piece of equipment with a slip clutch we would loosened the clutch, engaged the pto to make sure it was slipping properly and then readjusted it, several times equipment that sat for a year or so the clutch would rust/seize together and be a pain to break loose.
The few extra minutes it takes to do that and check everything can save time and money down the road

After a bit of welding and a REAL fun time getting the retainer clips both on the clutch and the yolk points, finally got mine all back together and mowed this weekend. The retainer clip on the u-joint end was much more difficult than the one inside of clutch assembly. Got everything back together though - clutch was definitely slipping more than it should at first so I just carried the tools on board to tighten 1/4 turn at a time until the slipping was minimized under regular cutting. The sound of shredding mesquite trees never sounded so good!

 

[TexasDigger]

That looked like it sounded rough. One of the things I like about my old same 75, I can ease the PTO on. Works great for the brush hog so that it doesn't jerk it around.

That's the main thing I miss about the tractor I replaced - on the old one, I could ease out the clutch on PTO engage & was much smoother to engage PTO - much less hit on the implement = less wear & tear. The slip clutch helps a little with this electric on/off - but only if I drop the RC all the way down in taller grass so blades have something to create some drag before engaging at idle. So far that has been the only thing that seems to help the initial "hit" - not a fan of the electric PTO engagement at all so far.

 

[TexasDigger]

You can think whatever you want but setting a pto clutch for a small pto hp tractor and use it on much of a bigger tractor with heavier loads, like tall thick grass, and the clutch won't last near as long.

Get in heavy grass with the bigger tractor and the clutch will slip a little here and there and wear it out much sooner. Those of us that have been using pto slip clutches for many years, have learned this from experience...

There is a little overlap, but it's a "little" not a lot.

SR

Found that out this weekend when back to mowing.. Made sure I was slipping enough to soften the blow on engagement but seemed like was still slipping a bit more than it should in taller grass. Carried tools with me and just cranked down the clutch screws 1/4 turn at a time until the slipping in tall grass was (almost) non-existent. Seems like it still takes a big of a jolt on engagement but not as bad as before. Seemed like engaging at idle with RC all the way to the ground in taller grass soften the impact a little on engagement and let the clutch do its job. If the RC breaks - will be good really excuse to buy a bigger one!

 

[Williy]

When I want to use the PTO I am at idle turn
the knob to start the PTO then slowly raise RPM's
up to 2200 and when I go to shut it down its at idle
then turn it off. Am I wrong in doing it like this???
shut the tractor down before I will attach anything
to the PTO. To hole the shaft to the yoke I only
have a #5 bolt that's the way it came also have
a slip clutch on the RC

willy.

 

[Fallon]

When I want to use the PTO I am at idle turn
the knob to start the PTO then slowly raise RPM's
up to 2200 and when I go to shut it down its at idle
then turn it off. Am I wrong in doing it like this???
shut the tractor down before I will attach anything
to the PTO. To hole the shaft to the yoke I only
have a #5 bolt that's the way it came also have
a slip clutch on the RC

willy.

Always engage the PTO at idle or close to it. I have yo bump up the RPMs slightly to engage my heavy flail mower or it might stall. Once engaged I generally just kick the throttle all the way up. Doesn't er how fast or slow once the clutchbis engaged. My flail has an overrunning clutch. So it doesn't matter what RPM I disengage at. The flail will keep spinning for a minute or 2 regardless. PTO shaft stops quickly though. Most of my other impliments are low inertia. Should probably idle down to disengage, but often don't.

 

[IndyIan]

Found that out this weekend when back to mowing.. Made sure I was slipping enough to soften the blow on engagement but seemed like was still slipping a bit more than it should in taller grass. Carried tools with me and just cranked down the clutch screws 1/4 turn at a time until the slipping in tall grass was (almost) non-existent. Seems like it still takes a big of a jolt on engagement but not as bad as before. Seemed like engaging at idle with RC all the way to the ground in taller grass soften the impact a little on engagement and let the clutch do its job. If the RC breaks - will be good really excuse to buy a bigger one!

My tractor has the same electric over hydraulic switch for the pto, and I broke the gr5 shear bolt on my 5' RC hitting the switch at near 540 pto rpm. The circlip was installed on the cutter shaft and held the pto shaft in place though, so there was no carnage.
Now when I was hooked up to a 5' round baler I stopped for some reason with about 4' of bale made and had to hit the switch with at probably 300 pto rpm(so the tractor wouldn't stall), and it started the round baler quite smoothly!
I wonder if the internal tractor pto clutch gets sticky from never slipping when starting a small pto load? My tractor also has an automatic pto engagement feature that it will start whenever you lower the 3pt and stop when you raise it, so it must be designed to engage fairly smoothly, but with a small rotary cutter, maybe it never slips at all and sticks after a while?

 

[TexasDigger]

My tractor has the same electric over hydraulic switch for the pto, and I broke the gr5 shear bolt on my 5' RC hitting the switch at near 540 pto rpm. The circlip was installed on the cutter shaft and held the pto shaft in place though, so there was no carnage.
Now when I was hooked up to a 5' round baler I stopped for some reason with about 4' of bale made and had to hit the switch with at probably 300 pto rpm(so the tractor wouldn't stall), and it started the round baler quite smoothly!
I wonder if the internal tractor pto clutch gets sticky from never slipping when starting a small pto load? My tractor also has an automatic pto engagement feature that it will start whenever you lower the 3pt and stop when you raise it, so it must be designed to engage fairly smoothly, but with a small rotary cutter, maybe it never slips at all and sticks after a while?

Haven't had a a chance to run anything larger on mine so not sure. I did talk to the guys at Larry Stovesand Equipment and they said the switch is basically just on/off and the only way to decrease the "hit" is to lower RPM's. They did recommend coming up from idle a couple hundred RPM's though for the hydraulics to flow more smoothly when engaging but sounded like no way to avoid the "hit" besides throttling down when you turn on the switch. Not sure if I would trust the auto on/off with a $5k tiller on the raise/lower feature - definitely not without a slip-clutch! If you keep breaking the sheer bolts on your RC even when throttling down, slip clutch is really only option to prevent having to replace the the sheer bolt all the time.

 

[IndyIan]

Haven't had a a chance to run anything larger on mine so not sure. I did talk to the guys at Larry Stovesand Equipment and they said the switch is basically just on/off and the only way to decrease the "hit" is to lower RPM's. They did recommend coming up from idle a couple hundred RPM's though for the hydraulics to flow more smoothly when engaging but sounded like no way to avoid the "hit" besides throttling down when you turn on the switch. Not sure if I would trust the auto on/off with a $5k tiller on the raise/lower feature - definitely not without a slip-clutch! If you keep breaking the sheer bolts on your RC even when throttling down, slip clutch is really only option to prevent having to replace the the sheer bolt all the time.

Oh yes, I always drop the rpms down to idle for the RC, and I put gr8 bolt in... it was breaking the gr5's pretty easily hitting minor stuff like ant hills.... Maybe a bad idea but my RC has a nice round stump jumper so it should fold the blades and save itself? I guess from your experience I know I don't want to break the input shaft on the cutter, as stuff will be flailing around!
I have ran a small square baler and it started up pretty smoothly as well. I'd have to look at my service manual tonight, but I'm quite sure there is still a pto clutch, its just engaged hydraulically now when you flick the switch.

 

[5030]

Always engage the PTO at idle or close to it. I have yo bump up the RPMs slightly to engage my heavy flail mower or it might stall. Once engaged I generally just kick the throttle all the way up. Doesn't er how fast or slow once the clutchbis engaged. My flail has an overrunning clutch. So it doesn't matter what RPM I disengage at. The flail will keep spinning for a minute or 2 regardless. PTO shaft stops quickly though. Most of my other impliments are low inertia. Should probably idle down to disengage, but often don't.

Once you euchre your inherently weak Kubota PTO wet brake you will, but then you have an over running clutch on the implement so you are good to go. If there is no ratchet clutch, I stick on a over running clutch on the pto stub. You don't want to ever replace that pto brake as it entails splitting the tractor.

 

[scootr]

Good thread. Good reminder to keep a couple of those #2 shear bolts in the tractor tool box.
Saves wasted time going back to the barn

 

[Sawyer Rob]

Once you euchre your inherently weak Kubota PTO wet brake you will, but then you have an over running clutch on the implement so you are good to go. If there is no ratchet clutch, I stick on a over running clutch on the pto stub. You don't want to ever replace that pto brake as it entails splitting the tractor.

Why would you replace it??

I'm glad my tractors don't have one, and if it did and I wore it out, yeaaa... lol

SR

 

[5030]

Because with no working pto brake the stub turns constantly so tell us how do you attach a pto shaft to a rotating stub???

 

[ptsg]

Because with no working pto brake the stub turns constantly so tell us how do you attach a pto shaft to a rotating stub???

Put the PTO in Neutral.