MInimum engagement of driveline tubes?????

   / MInimum engagement of driveline tubes????? #11  
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

Well I guess time will tell, but I've been using this extension for 5 years now only for the tiller averaging maybe 4hrs per year. At 540 pto rpm I don't feel any vibration whatsoever. If there is one bearing or seal that I would worry about, it be the mid pto as that one has some vibration when using the blower and then again....

Henri
 
   / MInimum engagement of driveline tubes????? #12  
I asked this very question of a friend years ago who was an engineer/designer for Borg Warner. He told me a good rule of thumb was six times the shaft diameter, don't know if that applies only to the square shafts or the newer shafts designs. That was what he considered as a minimum, so if you have an application that extends the telescopic length that has to be add to it. It stands to reason that a larger diameter shaft would need more engagement than a small shaft imo but I don't know with certainty as I am not an engineer.
 
   / MInimum engagement of driveline tubes????? #13  
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.
No argument. But consider that the topic is about Pat's Easy Change and PTO extensions. With PEC in the equation, that assumes three point operation.

//greg//
 
   / MInimum engagement of driveline tubes????? #14  
No argument. But consider that the topic is about Pat's Easy Change and PTO extensions. With PEC in the equation, that assumes three point operation.

//greg//

I got that. My comment was more about a consideration often overlooked when using extenders. The tendency may be to leave them on all the time. My tendancy is to avoid them because they are a Band-Aid that alters the intended geometry of hitch and driveline components. Even when used on mounted implements they have a negative effect on the front u-joint angle when the implement is raised when compared to a properly connected shaft. Shaft extenders are cheap, easy and almost never the best choice from a mechanical standpoint.
Others are free to use them if they wish.
 
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   / MInimum engagement of driveline tubes????? #15  
I asked this very question of a friend years ago who was an engineer/designer for Borg Warner. He told me a good rule of thumb was six times the shaft diameter, don't know if that applies only to the square shafts or the newer shafts designs. That was what he considered as a minimum, so if you have an application that extends the telescopic length that has to be add to it. It stands to reason that a larger diameter shaft would need more engagement than a small shaft imo but I don't know with certainty as I am not an engineer.
[Engagement] Length/Diameter ratio is an effective gage on resistance to cocking and binding. 6 is on the safe side, allowing tolerance for more slop before problems develop.
larry
 
 
 
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