drive line too short

   / drive line too short #1  

farmyid

Bronze Member
Joined
Sep 17, 2003
Messages
53
Location
Western Mass at 1500 feet elavation
Tractor
Century 3040
I am trying to get my new-to-me snowblower hooked up to the three point and find the pto drive shaft a bit short. This is complicated by the fact that the blower end is 1-3/4" six spline and the tractor end is 1-3/8" six spline. I found an adaptor between the two, but want to avoid the expense of replcing the whole shaft with the u-joints into which someone has already welded an adapter. Can''t I put something in there to make it three inches longer? Do they make very short extensions? Is there a slip clutch rhat could be added into the line to help defend against stones as well as take up room?
Thanks, Farmyid
 
   / drive line too short #2  
If you have a Tractor Supply store nearby, they sell extensions. Also, some folks install an overrun clutch which adds about 4" to your tractor's PTO shaft. A slip-clutch might give you the added dimension you need and also provide that protection you mentioned. All of those choices are easier and cheaper than replacing a drive shaft.
 
   / drive line too short #3  
I assume you have already tried making the toplink longer to kick the lower part of blower inward--Is there room for drilling 2 more holes for the snowblower lift arm pins to bring the blower 3 inches closer to the tractor--We do sell the overide clutch and slip clutch mentioned--If we can be of any help, feel free to contact us--Ken Sweet
Sweet Farm Equipment Co. *Since 1977*
 
   / drive line too short
  • Thread Starter
#4  
Nice ideas about trying to shift position of the blower, I have a feeling it won't work, but will look tommorow. What is the difference between an overide clutch and a slip clutch and which would be desirable in this application? If there is a shear pin as well (don't _think_ there is) would I replace that with something harder if I got a clutch in there? I assume the clutch will come in handt next year on a brush mower, or do they come with those built in? also the tiller? The blower (an old International) was very inexpensive as the previous owner had run the gearbox dry and then replaced it with the wrong speed (1000 Rpm) gearbox and couldn't run it fast enough with his tractor. I have a two speed PTO on mine so I guess I'm OK. Also had to change the pins to Cat.1 from Cat.2. Thanks for your help this is all new to me! Farmyid (Two inches on the ground at 9 degrees and a storm predicted for friday night in the 8" to 12" range)
 
   / drive line too short #5  
Slip clutch = prevents overloading kinda like a shear pin that doesn't need replaced

Overruning coupler = tractor drives the implement, coupler doesn't allow the implement to drive the tractor. Dropping the throttle from PTO speed to idle, a rotary mower, for example, will feed energy back through the drive till it slows down. Kinda like a driveline diode /forums/images/graemlins/smile.gif...............chim
 
   / drive line too short #6  
</font><font color="blue" class="small">( difference between an overide clutch and a slip clutch )</font>

Instead of "overide" it's called "overrun," but that's only important if you are doing an internet search and need to get the exact name. The overrun clutch is really a misnomer. It should be called overrun ratchet because it works like a ratchet in one direction only. When your tractor is applying power, it locks and transmits the power to the implement. As Chim indicated, if centrifugal force causes your implement to keep running after the power is removed, the "ratchet" action allows the implement to spin down normally. Some newer tractors with independent PTOs have a braking action on the PTO to slow the implement. An overrun clutch defeats that action. The overrun clutch is about $45.

A slip clutch is a better solution if you want to have one installed. I'm not sure of the price, but I think they are more than the overrun clutch. It replaces the shear pin's action. I'm pretty sure you have a shear pin on your snow blower. Look at where the U-joint attaches to the snow blower. Does it have a bolt through the U-joint collar? If it does, that is the shear bolt. If you hit a rock, that bolt will snap off and you will have to replace it with a new #2 grade soft bolt of similar size.

Finally, the PTO extension is available from many farm/tractor dealers, and Ken Sweet might also have these. They come in various lengths, but I don't think I've seen one less than +6". That might be too long for your application. If you can make the modifications Ken suggested, you might be better off. Adjustments like that are common between tractor models and is sometimes referred to as "setup" by tractor dealers.

Good luck getting the correct "setup" for your snow blower. /forums/images/graemlins/cool.gif
 
   / drive line too short #7  
You probably already have thought of it, but just in case - if you need another 3" of length, it would take another 6" of shaft (or other overlapping stuff) to make up the 3" needed..................chim
 
   / drive line too short
  • Thread Starter
#8  
Well after looking at it this morning I saw that the shaft was even shorter than I thought. After searching around I found a tractor repair buisness that offered to burn the old shaft out of the U-joint and replace it with a longer one for $50 plus the material ($18 or so) so I am going that way. My question is should I invest in a slip clutch anyway? I am worried about finding a cobblestone in my brothers driveway sooner or later. Will the shear pin protect the blower? I guess most of the more modern tillers and brush cutters I am likely to get in the future have built in slip clutches. Thanks everyone for your help! Farmyid
 
   / drive line too short #9  
I don't believe pto driven implements generally come with slip clutches, also each implement will probably need its own drive shaft, as different implements, brands, sizes, will all require a different length shaft.
 
   / drive line too short #10  
Gee I thought the name was Spraug clutch, like the one on a bicycle.
 
 
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