Should stump jumper be loose?

[genusCastor]

Maybe I'm to late but I would coat the whole spline area with never seize before you tighten everything up. It will be a lot easier to get apart the next time.

Yessir, done did. I put neversieze on errythang!

- djb

 

[stuckmotor]

Hi Guys,
Wotza stump jumper??
Ian

Ian,
If you look at the rust pitted, saucer shaped object in post #1 of this thread, you'll see a stump jumper. As the name implys, they hopefully allow a rotary cutter to ride over stumps rather than break something that you don't want broken.

 

[OzTinkerer]

Hi Stuck (or should I call you Mr Motor?),
Thanks for that. Sounds good in theory, but I'd think the blades passing in front of the 'saucer' would hit the 'stump' hard and often before the stump jumper gets there to ride over it... Still it's got to be better than a solid bar slamming into the 'stump'. I've not seen one of these on our local 'brush hogs' (we just call 'em 'slashers'). Something to keep in mind.
Ian

 

[stuckmotor]

Ian,
I honestly don't know how much good the stump jumpers do. My main slasher doesn't have one. I have a very light duity slasher which I bought to cut the grass that has a stump jumper but I'd be afraid to take it around stumps.
Stuck

 

[genusCastor]

...the rust pitted, saucer shaped object in post #1 of this thread...

:laughing:

That rust pitted saucer is a mechanism to allow the blades to be mounted so they can swing back and absorb the force if they hit something stationary, like a stump. Unlike a centrally mounted blade that has no way of absorbing the force. The name, stump jumper, may be misleading. It doesn't jump over anything.

Having said that, I wasn't sure if these things were mounted loose to allow even more movement of the blades in the event something is hit.

- djb

 

[jimmysisson]

The bevel on the edge of the disc helps it ride up over a stump. Jumping is a whole 'nother concept.
Jim

 

[Btown]

I got the stump jumper off, and the spindle looks fine, no damage. I reassembled and tightened the castle nut down, and it will, in fact, secure the stump jumper. But the nut goes up above the cotter pin hole, so what I think happened is that the castle nut backed down to the cotter pin. Why they would put a cotter pin in below the castle nut...? Maybe they just didn't tightnen it down all the way to begin with.

I'll need to add a shim to get the castle tight tightened at a location where the cotter pin actually secures the nut. There are a couple shims on it already, I have a piece of 5/16" plate, might try cutting a washer out of that. Get to play with...er...ah...I mean use the plasma cutter.

I have the bush hog up on blocks, can get to the blade assembly easy. Might try the tilt method next time tho...

- djb

My guess is it had a washer, at some point the washer was not put on, either at the factory or previous owner.

 

[RandyT]

Like somebody said the jumper designed to ride up over objects. the swinging blades will bounce back if they hit something, but the solid bar they are attached to won't and a direct impact with a hard object can bend the gearbox shaft, or in some cases can create enough force to rip the bolts from the cutter, or destroy the gearbox itself.