Attachment PTO Input Shaft Seems to Be Sized Wrong...

   / Attachment PTO Input Shaft Seems to Be Sized Wrong... #1  

dolai

New member
Joined
Apr 2, 2013
Messages
10
Location
Southern Ohio
Tractor
Jiangsu Model 504
I have recently procured a Chinese (like the Jinmas) chipper attachment. After some assembly and work, it seems ready for service. Trouble is, my PTO shaft will not mate on the attachment end.

With some caliper measurements, it seems that the diameter of the input shaft of the chipper is too large by about a mm in between the splines (30 mm, and my tractor measures I think closer to 29 mm if I'm correct). This looks like it is supposed to be a standard 6-spline 1 3/8'' (~35 mm larger diameter) shaft.

The PTO shaft that came with the chipper mates alright, though it's certainly more work on the chipper end then on the tractor end. The trouble is that it's two short for my application... hence the need for the new PTO shaft that I have cut to size and now won't fit.

Has anyone else run into this? What is the best way to deal with it? I'm tempted to break out the files and start whittling away at the chipper input shaft, but there has got to be an easier way... thanks ahead of time for the input!
 
   / Attachment PTO Input Shaft Seems to Be Sized Wrong... #2  
go to your local farm supply and buy the right yoke to fit your application. All you have to do is make sure the universal joint is the same size and it should change out easily.
 
   / Attachment PTO Input Shaft Seems to Be Sized Wrong... #3  
How much too short is the PTO? I had to get a longer one for my Chinese chipper. I found a shaft extender gave me the 3" overlap in the spline I needed. I had no trouble matching up the splines. A dealer I know that sells several brand names of Chinese chippers told me they use parts that are interchangeable with US stuff, even the chipper knives. Mine has all us bolt sizes for instance. He also told me all those chippers are made on the same pattern by only two manufacturers but market in many brand names including No-Brand. They change the bolts and brand names when selling to metric dominant countries.

Ron
 
   / Attachment PTO Input Shaft Seems to Be Sized Wrong...
  • Thread Starter
#4  
Yeah, based on the measurements that I got, I am pretty sure that this is a manufacturing error. It is supposed to be a standard 1 3/8'' six-spline shaft, but the dimensions are just a little bit off. I think the only reason that the supplied Chinese PTO shaft fits is that the manufacturing tolerances on that may be higher than the ones we usually deal with. So, unless I can find an off-the-shelf yoke with similarly poor tolerances, I think that swapping the yoke is a no-go. I did try getting another standard yoke from the local Tractor Supply, and it scores not fit in the same way. Another option would be to take the yoke that fits and move it to the longer shaft, but unfortunately these are nowhere near interchangeable. The supplied PTO yoke really looks non-standard. Are there any charts that might help?

An extension - now that's an idea that I somehow did not think of I only need 3-5 inches, I estimate without measuring. Are there extensions like this with 1 3/8'' six-spline on both ends?
 
   / Attachment PTO Input Shaft Seems to Be Sized Wrong... #5  
Yeah, based on the measurements that I got, I am pretty sure that this is a manufacturing error. It is supposed to be a standard 1 3/8'' six-spline shaft, but the dimensions are just a little bit off. I think the only reason that the supplied Chinese PTO shaft fits is that the manufacturing tolerances on that may be higher than the ones we usually deal with. So, unless I can find an off-the-shelf yoke with similarly poor tolerances, I think that swapping the yoke is a no-go. I did try getting another standard yoke from the local Tractor Supply, and it scores not fit in the same way. Another option would be to take the yoke that fits and move it to the longer shaft, but unfortunately these are nowhere near interchangeable. The supplied PTO yoke really looks non-standard. Are there any charts that might help?

An extension - now that's an idea that I somehow did not think of I only need 3-5 inches, I estimate without measuring. Are there extensions like this with 1 3/8'' six-spline on both ends?

Try this:

Extension Adapter - Tractor Supply Online Store
 
   / Attachment PTO Input Shaft Seems to Be Sized Wrong... #6  
The TSC item will not work unless you have a pin hole through the shaft on either end to lock them together with a PTO Locking Pin. If you can't lock them together it will come apart and bang around till you get it shut down. TSC does not list the part you need. The Part you need is a SPEECO #SP-16612. It has the locking collar like the PTO Shaft has on one end. It extends shaft 4 3/8".

Some tractor dealer should have it or can order it for you.

Ron
 
   / Attachment PTO Input Shaft Seems to Be Sized Wrong... #7  
Here's an option...
Pto Adapter

This is the type I have:
Tisco Tractor Part Mart: Reliable Tractor Parts You Need. Fast :: ADAPTOR (XB371)

Here's a listing with all types...
Double HH Quality Products - Don't Compromise... Demand Double HH

Another option is to replace the male or female shafts. This will take some work to determine the proper size and profile, but is an option. I'd go the adapter route myself assuming it provides the necessary overlap, but wanted to provide another option. This link has an exploded view of a PTO to better describe what I'm referencing. Refer to items 3 and 4.
2200 Series

Good luck and let everyone know your solution.
 
   / Attachment PTO Input Shaft Seems to Be Sized Wrong... #8  
I forgot your poor fit up. I would take a sharp file and trim out that 1mm until it fits right rather than replace the whole shaft like was suggested. Or, contact the supplier you bought from, they may replace the whole shaft under warranty, worth a try.

Ron
 
   / Attachment PTO Input Shaft Seems to Be Sized Wrong... #9  
Return it. You troubles have only begun if the shaft isn't right.


IMHO,
D.
 
   / Attachment PTO Input Shaft Seems to Be Sized Wrong...
  • Thread Starter
#10  
Thanks for all the help, folks.

I have called all of my local tractor parts suppliers, and none actually stock the quick-detach PTO extender. Went to TSC just to check, and surely enough they only have the one with the pin through it - and my tractor side does not have a hole through the shaft.
I will place an order for the appropriate size and let you know what the outcome is.

ddivinia, I appreciate the input, but I got such a screaming deal on this chipper that it's worth holding on to it. I have given it a pretty thorough once-over and made appropriate adjustments and lubed all of the appropriate points... also did spin it up with the too-short PTO shaft (I know, I know)... and it works quite well (I couldn't resist running a smallish branch through it).
It really looks like they forgot to finish machining the PTO input shaft. On closer inspection, there is a tiny groove on each side of each of the six valleys. They also didn't finish with the usual slope that goes up to the splines (it's a sharp 90 degree angle rather than a slope). Defective batch? Probably why the price was so good...
 
 
 
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