MInimum engagement of driveline tubes?????

[TNhobbyfarmer]

A year or so ago I added Pat's Easy Change to my lower hitch arms. That added an extra 4 inches distance from the rotary cutter to the PTO spline. I have been using the cutter ever since without incident. However, I got to thinking about how much engagement I now had in the metal driveline tubes so I measured. Only 5.5 inches. Is that problematic? I have put many hrs on the cutter since the change. Should I worry?

 

[RickB]

Usual published specification is 6". You be the judge.

 

[oldnslo]

How much does this change when you go over ridges or through ravines, etc. If you have put on many hours with no problems and the shaft still telescopes smoothly it sounds like you are still okay.

So much depends on the torque being transmitted, any shock loading, etc. that it is very difficult to say what is the minimum engagement required.

Example: How many MMM have 6" of engagement when tehy are in operation? I have never measured this on branson but I am estimating maybe 4" engagement when at cutting height.

 

[SPYDERLK]

A year or so ago I added Pat's Easy Change to my lower hitch arms. That added an extra 4 inches distance from the rotary cutter to the PTO spline. I have been using the cutter ever since without incident. However, I got to thinking about how much engagement I now had in the metal driveline tubes so I measured. Only 5.5 inches. Is that problematic? I have put many hrs on the cutter since the change. Should I worry?

Usual published specification is 6". You be the judge.

If that is the minimum engagement you have [varies with lift] and your tubes fit well so there is little side slop you will be ok til they wear enuf that appreciable side slop develops. ... Thats if you have the trochoidal tubes. If theyre solid square in square receptacle significant sideslop can be accomodated because the interlock is much more rigid and wont deform and bind as readily.
larry

 

[greg_g]

I don't feel comfortable with a mere 6" overlap, that's a worst case scenario in my book. When at max installed extension, I like to have as close to 1/3 extension as possible. Take a 42" shaft (collapsed) for example; it can safely operate at lengths between 43" and 60" and still maintain a nice safe 12" minimum overlap. It helps extend the lifespan of PTO shafts too. As was touched upon above, wobble increases as overlap decreases. The more overlap you can safely operate with, the longer your PTO shafts will last.

Regarding PEC + aftermarket extension device , I used both for hundreds of hours on two different tractors with nary an issue.

//greg//

 

[Henri88]

I've ran into the same situation you did a few years back. Bought my tractor and tiller new, cut the pto shaft at the right length and then a year later I bought a quick hitch. Now the shaft was only overlapping about 5 or 6'' and did not felt comfortable with that so I fix my problem with an extension. Problem solved and feel much better.



Henri

 

[sweettractors]

I don't like extensions, as the wobble puts excessive wear on all bearings and seals in the entire drive system. May be ok for limited use, however, sooner or later they will catch up to you. Ken Sweet

 

[RickB]

I don't like extensions, as the wobble puts excessive wear on all bearings and seals in the entire drive system. May be ok for limited use, however, sooner or later they will catch up to you. Ken Sweet

Couldn't agree more. Extensions also foul up the standardized dimensions between the end of the tractor PTO shaft and drawpin when using drawn implements rather than the more common (here) 3PT implements.

 

[k0ua]

I can tell you what I did, and you can do what you like. I was faced with the same problem. Rotary cutter was originally on Kubota B7500.. Was cut for that tractor.. worked fine, then I swapped that tractor for an L3400hst.. it worked but it was short, maybe 6 inches or so.. Then swapped for a slightly larger tractor my current Kioti Dk35se.. Now it is really bad, maybe 5 inches, Maybe..I looked at the extensions.. decided I did not like the wobble factor... I bought another longer PTO shaft..It was over $100, but hey I just bit the bullet, now I feel better. I have seen the 1/3 rule overlap in print.. I have also seen a couple of trashed PTO shafts on here from being too short. It can and does happen.

James K0UA

 

[SPYDERLK]

I don't feel comfortable with a mere 6" overlap, that's a worst case scenario in my book. When at max installed extension, I like to have as close to 1/3 extension as possible. Take a 42" shaft (collapsed) for example; it can safely operate at lengths between 43" and 60" and still maintain a nice safe 12" minimum overlap. It helps extend the lifespan of PTO shafts too. As was touched upon above, wobble increases as overlap decreases. The more overlap you can safely operate with, the longer your PTO shafts will last.

//greg//

This is true with the trochoidal shafts. ... the whole overlapped length effectively interlocks giving added stability with increased engagement. The rectangular shafts are, or are often constructed differently. ... On mine the square receptacle is just 5" long and welded to the end of a piece of round tubing. The solid rectangular portion slips inside, but regardless of insertion, only bears on the 5" long female. -- So, beyond about 5.25" insertion you have full bearing rigidity and are free of end effects. They are quite durable according to their 40 yr history on bushogs that I beat the crap out of.
larry