Rotary Cutter need advice on bush hog driveshaft

[EE_Bota]

I would ignore hydraulic line lengths...and concentrate on proper shaft overlap, and proper pivot points. If you hook the implement up, and go into a turn, the U-joints should be bent an equal amount for each U-joint, and the chatter will be related to the extent those angles are different. It is a bit nasty to have the pivot point wrong. It can be very nasty to have the shaft length wrong, or the shaft phase incorrect.

When I was a kid, square shafts seemed to be the norm..but most of my shafts now cannot have the wrong phasing, which is a nice plus for modern shafts.

 

[RoyJackson]

If not, the PTO adapter and ORC will give you a short extension - but don't expect more than about 4".

//greg//

The adapter does extend the tractor's stub about 4". That would increase the OP's overlap from 2-3 inches to 4-5 inches.
Don't know about the OR Clutch...but I don't think I'd want an adapter and an OR Clutch hanging off the tractor's stub shaft.

RickB has the best solution...buy a new, longer drive shaft. They're not cheap, but not all that expensive either. Definitely cheaper then a tractor repair.
I would definitely not want an implement climbing up a tire during operation!

 

[RickB]

The adapter does extend the tractor's stub about 4". That would increase the OP's overlap from 2-3 inches to 4-5 inches.
Don't know about the OR Clutch...but I don't think I'd want an adapter and an OR Clutch hanging off the tractor's stub shaft.

RickB has the best solution...buy a new, longer drive shaft. They're not cheap, but not all that expensive either. Definitely cheaper then a tractor repair.
I would definitely not want an implement climbing up a tire during operation!

Shaft extensions and the like are an acceptable crutch when asked to transmit 20 or 30 HP. There isn't one made that will stand up to a steady diet of 60-70 HP and added stresses caused by improper shaft joint angularity.

 

[RoyJackson]

Shaft extensions and the like are an acceptable crutch when asked to transmit 20 or 30 HP. There isn't one made that will stand up to a steady diet of 60-70 HP and added stresses caused by improper shaft joint angularity.

The adapter I bought is pretty robust. Nor was there any documentation or warning to use it with a range of PTO HP (to be honest, not documentation at all).
The bolded text...your opinion, or a factual statement for which you can provide justification?
I'd be more concerned about the side loads on the tractor's PTO stub shaft bearings then the PTO adapter failing.

 

[RickB]

The adapter I bought is pretty robust. Nor was there any documentation or warning to use it with a range of PTO HP (to be honest, not documentation at all).
The bolded text...your opinion, or a factual statement for which you can provide justification?
I'd be more concerned about the side loads on the tractor's PTO stub shaft bearings then the PTO adapter failing.

Are you going to start in again? I thought we were in agreement on this topic.
I have never seen a 540RPM PTO shaft extension successfully used on a 60-70 HP tractor; how's that?
I'd like to know why of the 116,000 plus TBN members you figure I'm the only one not entitled to post an informed opinion without a supporting list of footnotes.

It seems perfectly acceptable to you, however, to recommend the use of a shaft extension that will bring the OP's hitch and PTO shaft geometry further from the recognized and accepted ASAE standard (14 inches) for 540 RPM PTO shafts than it is to begin with.

 

[LittleBlueTractor]

One thing I have read, but no supporting links...use of a PTO extension can cause premature wear on the tractor's PTO mechanism. IIRC, it was due to the lengthening of the stub shaft (of the tractor) putting more loads on the bearings.

Sure wish you knew a little more about this Roy. I have an over-running clutch on my tractor's PTO shaft (EXACTLY like the one in grsthegreat's post) and I use my cutter pretty often. Makes sense the the added weight would have some effect on the bearings. Don't know how much it weighs, but it's not something you could forget about in your hand -- maybe 6-8 lbs. I only have 24 hp at the PTO, so I'm not too worried about breaking it. I got one because they seem to be cheap insurance.... Now I'm concerned about wearing out the PTO prematurely. Couldn't find anything on the intertubes about the subject though.

 

[grsthegreat]

Sure wish you knew a little more about this Roy. I have an over-running clutch on my tractor's PTO shaft (EXACTLY like the one in grsthegreat's post) and I use my cutter pretty often. Makes sense the the added weight would have some effect on the bearings. Don't know how much it weighs, but it's not something you could forget about in your hand -- maybe 6-8 lbs. I only have 24 hp at the PTO, so I'm not too worried about breaking it. I got one because they seem to be cheap insurance.... Now I'm concerned about wearing out the PTO prematurely. Couldn't find anything on the intertubes about the subject though.

well the Kubota dealer here sells them and said they doubted it would affect anything. He has installed these and shaft extensions for a long time and as far as he knew he did not have any issues with them....as far as he knows.

When im using my chipper the pto shaft is completely horizontal ....no bend at all, so i dont see how it can affect anything. Now if i was to continually raise and lower under power...than maybe i can see some future issues.

The only other implement i use the OR clutch on is the brushhog, which only gets 4-5 hrs a year worth of use. So I personally am not going to lose any sleep over. Now if i did alot more mowing...whatever... then i would seek out some more info on the matter.

 

[RoyJackson]

It seems perfectly acceptable to you, however, to recommend the use of a shaft extension that will bring the OP's hitch and PTO shaft geometry further from the recognized and accepted ASAE standard (16 inches) for 540 RPM PTO shafts than it is to begin with.

Yes...as long as the user realizes there is a pitfall to extending the PTO stub shaft. It's called making an informed decision.
BTW, after being on the "Friendly Politics" forum, with so much hearsay and BS being bandied about, I'm getting in the habit of asking for supporting data. Sorry about that...but, even on nonpolitical forums (such as this one), supporting data does provide for a more authorative post, doesn't it?

Sure wish you knew a little more about this Roy. I have an over-running clutch on my tractor's PTO shaft (EXACTLY like the one in grsthegreat's post) and I use my cutter pretty often. Makes sense the the added weight would have some effect on the bearings. Don't know how much it weighs, but it's not something you could forget about in your hand -- maybe 6-8 lbs. I only have 24 hp at the PTO, so I'm not too worried about breaking it. I got one because they seem to be cheap insurance.... Now I'm concerned about wearing out the PTO prematurely. Couldn't find anything on the intertubes about the subject though.

As I responded to RickB...just know any risk, and remove it from the tractor when you don't need that extra length. I use mine for my chipper...don't need the extra length for anything else (at this point in time). But it is something to consider if you add the Pat's Easy Change or a Quick Hitch (which is why I bought it in the first place...I had the Pat's Easy Change on my old 790).

Now, I cannot recall where I read this (about the extra wear) and I did Google using the query "can a pto adapter damage a a tractor?"...so, I have no supporting data I can lay my hands on at this time (shame on me!).
Did find an interesting .pdf file and link though: http://www.newtoncrouch.com/files/faq/pto_adjustment.pdf

 

[greg_g]

I have never seen a 540RPM PTO shaft extension successfully used on a 60-70 HP tractor; how's that?

Based upon my own experience, I'd say that's likely an accurate statement. I had the PEC system on both my 35hp and 45 hp tractors. To make up for the additional 4" extension of the lower lift arms, I installed the PTO adapter on both tractors. I wore them out faster on the 45hp than I did on the 35hp. Vibration wears the inside surface of the retainer pin until there's not enough material left to hold it in the PTO stub locking groove. So I'm pretty sure that adapter lifespan is inversely proportional to PTO horsepower. Can't speak to ORCs though, never owned one.

//greg//