Rotary Cutter Bush Hog stump jumper question

[PM1]

I have a Bush Hog SQ720 rotary cutter that I use hard. It has an oval pan, or stump jumper, around the blade holder. After enough collisions with stumps, the oval pan gets bent out of shape. With an oval shape, the pan repeatedly hits a stump as its long axis rotates around.

It seems like a round stump jumper wouldn't have this problem since there is no long axis to swing around and collide with the stump at high speed. I've never used a cutter with a round pan, so I'm only theorizing. Am I thinking about this correctly?

 

[Farmwithjunk]

I have a Bush Hog SQ720 rotary cutter that I use hard. It has an oval pan, or stump jumper, around the blade holder. After enough collisions with stumps, the oval pan gets bent out of shape. With an oval shape, the pan repeatedly hits a stump as its long axis rotates around.

It seems like a round stump jumper wouldn't have this problem since there is no long axis to swing around and collide with the stump at high speed. I've never used a cutter with a round pan, so I'm only theorizing. Am I thinking about this correctly?

The SQ series mowers are light to medium-light duty mowers. They aren't really intended for use in extremely hostile conditions. They are an economy level mower from Bush Hog's point of view. If you're "repeatedly hitting stumps", I'd say you are most likely using a mower below the recommended duty rating.

On the heavy duty lines, the stump jumper pan IS round. But, speaking from experience, hit a stump even with a round stump jumper, and you'll still get quite a pounding until you either pass over the stump OR raise the mower up away from it.

 

[PM1]

Thanks for your reply. I definitely use this cutter in far more hostile conditions than it was intended for. After 6 years of rough use, however, it continues to hold together relatively well.

The oval stump jumper, however, eventually gets bent out of shape and prevents the blade from swinging freely. The only solution I've found so far is to replace the blade holder / pan unit, and that's relatively expensive.

I was hoping that I might be able to replace the oval pan / blade unit with a round pan / blade unit (perhaps from a heavier Bush Hog cutter). I already use heavier blades designed for one of their heavier cutters (the original blades sheared off).

I know any cutter will shudder hard when it hits a stump; I'm just trying to figure out a way to reduce the damage to the stump jumper pan so I don't have to keep replacing it. I know the obvious answer is to avoid the stumps...

 

[skipmarcy]

Maybe you can find an old rotary cutter with a rusted-out deck or bad gearbox that you can salvage the pan from. My old Howse cutter has a round one and must be a pretty heavy one as I've abused it for 10 years now and it has no dents or bends and it was long-used when I bought it!!! I paid $300 for it and all it needed were the 2 u-joints for the driveshaft.

 

[MarkLeininger]

I ditto looking for an old one, back when they were built out of battleship steel. I bought an old used Ford bush hog that I think weighs more than my tractor. It has a round pan that looks like it's made out of 1/4" steel. I paid $350 for it, but it was a project getting it home.

 

[Farmwithjunk]

Thanks for your reply. I definitely use this cutter in far more hostile conditions than it was intended for. After 6 years of rough use, however, it continues to hold together relatively well.

The oval stump jumper, however, eventually gets bent out of shape and prevents the blade from swinging freely. The only solution I've found so far is to replace the blade holder / pan unit, and that's relatively expensive.

I was hoping that I might be able to replace the oval pan / blade unit with a round pan / blade unit (perhaps from a heavier Bush Hog cutter). I already use heavier blades designed for one of their heavier cutters (the original blades sheared off).

I know any cutter will shudder hard when it hits a stump; I'm just trying to figure out a way to reduce the damage to the stump jumper pan so I don't have to keep replacing it. I know the obvious answer is to avoid the stumps...

I'm gonna go WAAAAY out on a limb here and make a few guesses. I have a Bush Hog 286, a 297, and a 406 mower. I have parts manuals for them. I DON'T have a manual for any of the SQ series. SO... Parts commonality between the models is in question. Will the heavier round stump jumper pan of a 286/296 fit an SQ172? My guess is no. The heavier models have heavier duty ratings on their gearbox. I would assume that includes a heavier output shaft. Probably a larger diameter..... Next suggestion would be to contact Bush Hog directly. OR... Find a GOOD Bush Hog retailer and query their parts man. Next step would be, swap gearbox and pan from a larger model Bush Hog, replace entire mower with heavier duty mower, OR, look for an older, heavy duty USED mower. In the interim, I'd make certain the slip clutch is adjusted correctly to allow some "give" when you get into a stump.

 

[kthompson]

I wish I could remember where I saw it but not too long ago saw a heavy duty rough cut mower with a about an inch thick round steel plate and NO pan. Really made sense to me. Do not remember if the blades were on the top or bottom of the plate.

This may help:
STUMP JUMPER 60HP - Agri Supply

But those stumps, are you cutting same place over and over, if so, remove them. You may need to raise the cutting height also.

 

[sld]

I never fully understood how the stump jumper works. When mowing, with the rear slightly higher than the front, the blade(s) will hit the stump well before the round pan called the stump jumper.

Is it to keep you from repeatedly hitting the same stump?

 

[skipmarcy]

The way I understand it is that it's not to help the blades in any way, they will swing away and hopefully not crack. It's mainly to keep the output shaft from snagging the stump and stopping you dead in your tracks and breaking all kinds of components. I would assume the ones with just a flat metal disc for the blades to mount on isn't really considered a stump jumper, I would think it needs to be the "pan" type with the bevelled-up edge so it rides up and over the stump. It's not really made to continually hit stumps, just to hopefully save you from severe damage on those "rare" occasions one finds you not paying attention !!

 

[PM1]

Thanks for the helpful replies. I'll look into whether I can swap out some components to end up with a round pan. If not, I'll look for an older or used cutter.

I appreciated the link showing the round stump jumper -- that's just what I had in mind. I think a round pan like that would suffer far less damage from a collision with a stump since it never "swings around" into the stump like an oval pan does.

As for avoiding or removing the stumps, I'm continually mowing blind into new areas and cutting trails and clearing heavy growth. Even stumps that I cut down to grade seem to grow taller with repeated mowing -- I'm sure that's because the tractor wheels compress the soil on each pass to make the cutter ride lower while the stump remains unchanged.