Driveline Length

[confederatemule]

At what position is a rotary cutter gear box at it's furthest distance from the tractor out put pto shaft? I think my new shaft is too short.

 

[Cougsfan]

I doubt seriously that the answer is the same for each tractor. It isn't too hard to measure and find out for yourself, nor is it that hard to just shorten the driveshaft.

 

[Roadworthy]

The rotary cutter is furthest when down and closest when up. I like to cut my shaft as long as possible. That means I measure the distance when up then subtract a couple of inches to make sure it won't bind. On my tractor and mower combination I have about a five inch difference between full up and full down. You always want to cut the same amount from each part of the shaft. If it needs to be six inches shorter you will cut six inches from each half. The drive shaft material can be purchased separately from the drive shaft and varies widely in price. This year I paid about $100 for an inner and an outer about five feet long each then cut to length and installed into the ends. I reused the old shield.

 

[oosik]

My Wallenstein chipper is my only PTO driven implement. I spent the better part of a day figuring out drive shaft length for the chipper. The time was spent trying to figure out all the various described methods of measurement. I must be REALLY dense but each described method gave me a different answer. Some didn't even make good sense!!! A whole lot of this confusion is because many of the explanations assume you have knowledge of certain facts.

I ended up doing it this way. Full connection of the chipper - minus the PTO shaft. Separate the shaft into its two parts. Connect half to the tractor PTO stub - other half to the chipper PTO stub. With my son running the tractor - he would raise/lower the rear 3-point while I held the two shafts - side by side.

This gave me the EXACT point where the chipper was closest to the tractor and how much needed to be trimmed off both shafts.

I ended up with a little over 12 inches of overlap and 3 inches of clearance before the shafts would touch either PTO universal joint( called bottoming out).

 

[ROUSTABOUT]

My Wallenstein chipper is my only PTO driven implement. I spent the better part of a day figuring out drive shaft length for the chipper. The time was spent trying to figure out all the various described methods of measurement. I must be REALLY dense but each described method gave me a different answer. Some didn't even make good sense!!! A whole lot of this confusion is because many of the explanations assume you have knowledge of certain facts.

I ended up doing it this way. Full connection of the chipper - minus the PTO shaft. Separate the shaft into its two parts. Connect half to the tractor PTO stub - other half to the chipper PTO stub. With my son running the tractor - he would raise/lower the rear 3-point while I held the two shafts - side by side.

This gave me the EXACT point where the chipper was closest to the tractor and how much needed to be trimmed off both shafts.

I ended up with a little over 12 inches of overlap and 3 inches of clearance before the shafts would touch either PTO universal joint( called bottoming out).

Does it take you three hours to watch 60 Minutes?

 

[oosik]

Ha, ha - - you ARE funny!! I don't watch 60 Minutes. However - it does take two times to watch most football games. Third quarter is usually sleepy time and I watch a second time on the rerun.

 

[CobyRupert]

Typically the shortest distance a PTO shaft needs to telescope is when the shaft is horizontal. Subtract a couple more inches if you want to connect or disconnect the pto at this position and it needs to slide back more to clear the pto shaft on the tractor.

IMHO, the longest it needs to telescope is either “all the way raised” or “all the way down”.
…but don’t assume flat ground testing gets you these results.
For example, consider a lowered rotary mower that you back over a bank while tractor remains on top. The shaft has to extend a lot more than if lowered on flat ground.
I once had the front of a 7’ rotary mower catch on a stump and stand it up almost 90 degrees vertical behind the tractor. I thought it was going to swing over onto my seat. I have no idea if shaft was close to bottoming out or pulling apart. Probably depends on lift arm height.

Bottom line: Make shaft as long as possible, with as much overlap, without it bottoming out at shortest (horizontal) position.

 

[stumblinhorse]

At what position is a rotary cutter gear box at it's furthest distance from the tractor out put pto shaft? I think my new shaft is too short.

If it is brand new, then what is the length of the 2 shafts compared to each other? A new shaft is pretty long. But if the other shaft has been cut down you won’t get much overlap. From my experience rotary cutter pto shafts usually come very long. But if you bought a new shaft they come in different lengths for different applications. My snowblower pto is very short compared to my rotary Cutter. And I needed to cut my blower shaft even more. I got very lucky and found a brand new comer replacement slip clutch side for my rotary cutter on eBay. If was cheaper than buying replacement clutch discs for my current comer. It was super long brand new…

 

[ericm979]

At what position is a rotary cutter gear box at it's furthest distance from the tractor out put pto shaft?

Probably when the top link is fully extended, tilting the mower back.
Next would be when the mower is fully lowered to the ground.

I think my new shaft is too short.

You might need a longer one. Better to be safe than injured. PTO shafts cause a lot of tractor injuries.

I'd want at least 6" of overlap at the worst position. A rotary cutter PTO shaft is pretty long, so there's a lot of wiggle room between short enough and too short. Something like a PTO chipper or forestry winch has a much shorter shaft and getting the proper length is more critical.

Last time I shortened one I made the outer plastic cover 1/2" shorter than the shafts. That way when assembling the two halves I don't have to line up both the shafts and the covers at the same time.

 

[mcfarmall]

I trim mine so that I can uncouple the shaft from the tractor at any point in the vertical travel of the implement. Doing this you can't go wrong.