Correct way to determine length of PTO shaft?

Tags · Jun 15, 2012

I am purchasing a used PTO powered spreader and was wondering if there is a standard way to figure the correct length of the PTO shaft and what the minimum overlap the shafts need for safe operation.

smstonypoint · Jun 15, 2012

There's a video here that should help:How To Video Demos - Implements & Attachments*

Steve

* I couldn't get the link to direct you to the specific video -- it's on the fifth row for my browser (FF).

gwdixon · Jun 15, 2012

Minimum overlap of the two shafts should be around 6" - more is better.

Maximum length should give you about 4" from your tractor's PTO point when fully compacted (slid together). This allows for easier attachment and allows the 3PH to be raised and lowered without binding.

However, there are heavy duty PTO shafts that have a 4" long bushing on the end that is the only engagement. In order to shorten it you have to cut off the bushing and weld it back on the shortened shaft. (from Tractor Supply)

Oh, and I store my PTO shafts apart (in two pieces) and lightly greased. Some shafts only go together one way so a little grinder mark is made on the ends of the shafts to show how to line it up for re-assembly.

shortthrow50 · Jun 15, 2012

Tagging for future reference

Bird · Jun 15, 2012

Bush Hog has manuals online. You might find pages 9-10 of this manual interesting.

boggen · Jun 15, 2012

smstonypoint said:
There's a video here that should help:How To Video Demos - Implements & Attachments* Steve * I couldn't get the link to direct you to the specific video -- it's on the fifth row for my browser (FF).

Bird said:
Bush Hog has manuals online. You might find pages 9-10 of this manual interesting.

one thing in video vs PDF manual., is the video goes into some detail about cutting the PTO shields a little bit more than what you cut the shafts. so when you go to slid both ends of the PTO shaft back together. you can actually do it. vs hassling around trying to blindly get ends of the pto shafts to slide back together.

fully raised or fully lowered will most likely cause PTO shaft to "extend" vs contract the shortest amount. when the PTO shaft is level maybe a little higher or lower than being level, is most likely when PTO shaft will be at the shortest collapsed length.

they say 6" min overlap. and if shaft allows longer the better. i can get myself into some pretty hairy situations, going through gulleys and ruts, going over a log or rock. that can cause 3pt hitch equipment to really bend and cause PTO shaft to expand (lengthen). more so on pull behind equipment like a trailer or something, that does not directly attach to the 3pt hitch. with that noted, if you have a choice between a shaft that just barely gives 6" overlap vs a longer PTO shaft that will give more overlap, i might pay a few extra bucks, for the longer shaft and cut it down as needed. for those things that are like trailers (manure spreaders) and like. so when i go over that pile of crud, or tire goes down into a rut. the shaft does not pull apart.

things that physically attach to 3pt hitch (both lower arms and top link) 6" overlap most likely be ok within reason, due to implement can only go so far due to 3pt hitch ability to only go so far up or so far down.