PTO DRIVE SHAFT OVERLAP

[k0ua]

Here is one pamphlet on PTO overlap. It mentions 2 inches from bottoming out, and 1/3 of PTO shaft overall length of overlap

http://www.newtoncrouch.com/files/faq/pto_adjustment.pdf

 

[k0ua]

This landpride chipper manual calls for 1/2 overlap.. So the consensus is there is no consensus. 6 inches, 1/3 overlap, 1/2 overlap. Take your pick, but I say the more overlap the better, as longs as the halves don't bottom out.. The longer the shaft, the more overlap you need in inches, but if you use a ratio formula it should work for all lengths. I am sticking with my 1/3 story.

 

[Oldoak]

I say the more overlap the better, as longs as the halves don't bottom out..

Yep, that has always been my thinking. And the way I sized a PTO drive shaft for my tractor the few times I had to cut one down to fit. I also keep the shafts well greased along with the universal joints.

 

[k0ua]

Yep, that has always been my thinking. And the way I sized a PTO drive shaft for my tractor the few times I had to cut one down to fit. I also keep the shafts well greased along with the universal joints.

Yes, greasing the shaft is often overlooked by a lot of people, and that is why you hear these horror stories of the shaft seizing up. It makes sense to me that the fact that the shaft is constantly moving in and out as the implement is going over the terrain, that the shaft could use some lube.

 

[DieselBound]

I think that the variance lies with USE/IMPLEMENT. Different implements seems to have different requirements. Rotary cutters seem to have a lower overlap requirement while chippers seem to require a greater overlap. The Newton site looks like it's focused on spreaders and sprayers: what the PTO demands are here isn't clear to me; but, it's a different kind of application than that seem by rotary cutters. I'd think that rotary cutters, especially any operating in tough brush, would require a greater overlap.

Shaft that I am looking at (well, I went ahead and ordered it) will give me the 1/3 value at working length. This comes out to a 13" overlap (with 60" maximum shaft length). Again, Bush Hog states 6" as minimum. I am also going to go with a series 6 shaft rather than a series 4, which should give me a bit more strength. I suppose, however, that the slip clutch is supposed to intervene if the shock/torque loading gets too high such that it would start to deform the shaft (hammer U-joints) or the tractor's PTO.

Reading in another thread I saw it recommended to use Fluid Film for lubing the shaft. I'd never lubed a PTO shaft before (wasn't aware of this need), but will certainly be doing it now! (why this site is so great- you learn a lot of important stuff here!)

 

[k0ua]

Fluid Film would work, but to save the More costly FF for other uses, I just slather the inner shaft with my regular grease, and put a good amount on the inside of the outer shaft and put them together. Once a year should be suffecient, unless you store outside all the time in the weather, then more often as needed.

 

[Oldoak]

Fluid Film would work, but to save the More costly FF for other uses, I just slather the inner shaft with my regular grease, and put a good amount on the inside of the outer shaft and put them together. Once a year should be suffecient, unless you store outside all the time in the weather, then more often as needed.

:thumbsup:

 

[DieselBound]

To add a data point here...

Bare Company, from whom I'm ordering a PTO shaft from, says that their 39" collapsed and 65" extended shaft has a 15" overlap. So, I would guess that they are good with being less than 2/3 but better than 1/3. I picked this shaft because the 65" allows the possibility of running the cutter off of a quick hitch; and, it also has a convenient mechanism for getting the guard tubes out of the way (allows for easier hook-ups).

 

[Rara Avis]

Depends on the component...but 6 inches is minimum...In the collapsed position the driveline should be approximately 2" from bottoming out to prevent possible damage to the tractor or implement.

BEFCO - Technical - Technical Tips - Adjusting the Drive line to the correct length.