Power requirements for PTO stump grinders

Captain Dirty · Oct 22, 2020

I am investigating PTO stump grinders and have questions on power requirements.

Manufacturers usually specify a range; some specify wider or narrower ranges for the same machine on different pages, typically 5 HP at the top or bottom. I surmise that, because the operator controls the feed rate, he can adjust the load to the power of his tractor. From my reading and from my experience with chippers, it appears that weight is a desirable attribute. I personally prefer an underpowered chipper with a heavy flywheel to the converse.

The consideration at the moment: Kubota says I have 32 HP at the PTO. Shaver makes a 24 inch diameter machine weighing 832# requiring 15 to 35 HP. For a 15% premium they make a 34 inch machine weighing 1180# requiring 35 to 100 HP. Does anyone have experience to recommend either in my situation? Would you prefer to buzz through a stump with the smaller or chew through the stump with the larger machine? I have some 30+inch oaks, maples, and pines, many 12-14 inch, and lots of rocks..

Peter 315 · Oct 22, 2020

You might be better off renting a stump grinder in the long run.....:2cents:

Sawyer Rob · Oct 22, 2020

It depends on what stump you are grinding. IF, it's a bigger hardwood stump, it takes quite a bit of power, unless you want to go so slow it's like watching grass grow.

Pine stumps grind much faster and make the grinder/tractor look pretty good...

Woodland Mills seems to have the cheapest grinder, that in my opinion is about the smallest/cheapest grinder to put on a three point, that I would buy...and that's the one I bought.

BTW, rocks and stump grinders do NOT mix!!!

SR

LouNY · Oct 22, 2020

With lots of rocks, depending on the surcharges for broken or missing teeth.
Fast moving carbides and rocks don't get along real well.

I have seen this style at work in our stony ground and it was impressive,
slow turning and just ate right down through the stumps.
Stumpex Auger Stump Grinder | FECON
renting a skid steer with one of these would be a good way to remove stumps.

Halftrack · Oct 22, 2020

Either Shaver is going to require 2 hydraulic circuits. I have used a similar 24" machine behind my TC33D and had to work slowly to get through the big stumps and not kill the tractor. You do NOT want the bigger machine. I would take Sawyer ROB's suggestion of the Woodland Mills machine for a cheap, simple unit, assuming you have hydrostatic drive.

Racy2 · Oct 25, 2020

I have the Woodland Mills stump grinder. The Massey sub compact I had only had about 18hp at the PTO. It would stall the tractor pretty easy if you were not careful. The level of the ground around the stump sometimes makes it difficult to apply even pressure. I now have a 40 hp tractor. I think the PTO is 35 HP. Looking forward to trying this with the stump grinder. The stump grinder has a slip clutch built into the PTO shaft in case you put to much power behind it. The bigger tractor will also stabilize the stump grinder better. My little tractor would really move around a lot with the stump grinder before. So before I was at the bottom range and now I will be at the top range.

Sawyer Rob · Oct 25, 2020

Halftrack said:
Either Shaver is going to require 2 hydraulic circuits. I have used a similar 24" machine behind my TC33D and had to work slowly to get through the big stumps and not kill the tractor. You do NOT want the bigger machine. I would take Sawyer ROB's suggestion of the Woodland Mills machine for a cheap, simple unit, assuming you have hydrostatic drive.

OR creep transmission gears...

SR

jmoneil · Oct 26, 2020

Had a Woods TSG50. Used it on a L3800 then on a MX5200. Removed about 150 stumps. All hardwood, mainly ash due to ash bore. If you are considering this type of grinder, even with the MX5200, it was slow going. Weight for stability and PTO horsepower definitely are items for consideration. I wouldn't do it over again with anything less than a MX size tractor.

Sawyer Rob · Oct 27, 2020

I power mine with a 45hp farm tractor and it does a pretty good job,

I ground 32 stumps on that job, some were hardwood stumps, that were at 31 inches, Big hardwood stumps do take a lot of hp...

SR

Captain Dirty · May 24, 2021

UPDATE

Thanks to all who responded to this thread and to the many who commented in other threads on stump grinders. I did buy and have now used a Quick Attach Attachments LLC "Stump Eater" 3 point Stump Grinder with a 24” wheel and with lift and swing cylinders. Halftrack was most direct, “You do NOT want the bigger machine”. Many others described stalling, bouncing, and other symptoms of underpower. I have now discovered grinding stumps puts a heavy, near constant load on each pass. I have had to feather the swing feed to keep from bogging down in pine and ash (the only species I’ve ground so far). The bigger (34") machine would probably be worse with my 32 hp..