Measuring/cutting PTO shaft on trailed implement

[feazel]

Hi Guys

Does anybody know of a good method of determining the correct PTO shaft length for a trailed machine? Plenty of info out there for mounted, which is set the shaft at horizontal and measure/cut to suit as the shaft will always elongate if the machine is lifted/lowered. But on a trailed machine you need to account for the tractor stub getting closer to the machine if you go through a hollow in the ground etc?

Cheers

 

[Lincs Lass]

Could you pull the shaft apart ,fit the machine end ,,fit the tractor end and see how much is left between the two tubes ,,on a trailed machine there wont be as much movement as a linkage mounted ,as long as the shaft doesnt bottom out when you turn which in theory would be the same as going into a hollow .
Is it a single or double knuckle UJ

 

[feazel]

I reckon trailed would have more movement. Especially going through a really short sharp hollow when the tractor is going up one side as the implement is coming down the other.

Thought there might be a rule of thumb

 

[johnflimston]

With trailed machine shaft is much longer so you have a bit more to play with.
Trouble with mounted machines is what is right for one tractor is not for another

 

[Pheasant Surprise]

I reckon trailed would have more movement. Especially going through a really short sharp hollow when the tractor is going up one side as the implement is coming down the other.

Thought there might be a rule of thumb

Measure twice, cut once?

It usually take a couple of goes to get it just right. Taking off gradually more of the length, but not too much as you need to.

I found the trailed batwing was quite tricky to get right first time as you can set the min shaft length up in the yard, on the straight ahead. But as you say if you have some undulating ground deepish hollows can catch you (or the shaft) out. Having the raise/lower wheels at the very end of the machine makes the "problem" worse. So need to set it for the highest raised height (travel height) of the machine and then (carefully) check the shaft won't nip up by driving over the deepest hollow you will come across.

Can you sum that lot up in a rule of thumb?

 

[Kiwi Pete]

Piece of string between the two splined shafts at the shortest distance you can make them

Less the length of both UJs

Folded in half, is the length per tube

No fag packet required

 

[jpd]

that is indeed common sense and very clever

 

[Bob c]

Piece of string between the two splined shafts at the shortest distance you can make them

Less the length of both UJs

Folded in half, is the length per tube

No fag packet required

but allow for overlap on tubs as well

 

[Pheasant Surprise]

but allow for overlap on tubs as well

Also allow enough to slide to be be able to take the shaft off the stub too, but usually there's enough play there as that's not the min length when you fit up.

 

[Kiwi Pete]

Not nice when they bottom out and jam onto the PTO BTDT

 

[jonny]

Think the max length used to be 2" less than the button to button measurement from tractor to machine

 

[Pheasant Surprise]

I was looking for something else in an ops manual and found this "method statement" and worked example for shortening a PTO shaft:

1. Connect the implement to the tractor. Position the PTO axles as close as possible towards each other.

2. Measure distance “A” of the PTO axles.

3. Measure distance “B” of the PTO shaft.
(See drawing for measure points)

4. Subtract length “A” from length “B”

5. Shorten the PTO with the solution. (See example)