Would this motor work for a stump grinder

[woodlandfarms]

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My tractor is rated at 3200PSI and 18GPM... I am still learning about how hydraulics work and how this would fit into my system so I ask because I am sure I am missing something important... Have yet to figure out all the logistics, but the stump grinder that fits my tractor is $1900 so I think I can build it cheaper...

 

[JohninCT]

I think that you could make a grinder work with that motor. BUT! I would suggest that you not directly connect the grinder blade directly to the motor. Power Trac stump grinders (at least the PT 425 motor/cutter I got) have a 1" dia shaft directly connected to the cutter blade. The problem with this I believe is that this relies on the hyd motor bearings to carry the loads from the cutter. Stump grinding puts a large side load on the shaft and I don't think that most of these motors have bearings that can handle that load. I burnt up one hyd motor on the stump grinder that I made. A better setup I think would be to run a smaller cutter blade faster and on a separate shaft with its own bearings. You could connect a chain drive between the hyd motor and cutter shaft. This would also give you some design flexibility to adjust cutter speed by using different sized sprockets. If you don't want a chain drive you could couple the hyd motor to the cutter shaft with a lovejoy coupling. Just make sure that the cutter shaft has its own bearings to handle the cutting loads.

Check out this site for ideas on stump grinders with smaller faster blades on a separate shaft. You can buy shaft assembly and cutter blades in their spare parts section.

Praxis 13hp Stump Machine

 

[Soundguy]

I agree witht he pillow bearings on the shaft.. but not the chain drive... chain and belt drives are ineficient power hogs...

Soundguy

 

[Renze]

...but belts do take away a lot of vibrations from both the stump cutting wheel and the motor.... In certain New Holland choppers, the CAT engines broke their crankshafts because the cutter drum and the engine were vibrating at the same frequency, which caused resonation, and in the end broke the engine crankshafts.

When you know how poor the efficiency of a hydraulic motor is, you will bit your tongue off about the efficiency of the belt or chain drive...

 

[woodlandfarms]

Check out this site for ideas on stump grinders with smaller faster blades on a separate shaft. You can buy shaft assembly and cutter blades in their spare parts section.

Praxis 13hp Stump Machine

This is WAY cool... I don't have access to a machine shop so I am limited to to welding and drilling and some cutting or farming it out to the local machine shop. What kind of Hydraulic motor would you mate this with? This is designed for 13HP, how about 33HP that I think the PTO puts out?

This is what I was initially working with in my head

Rayco Super Tooth: The Best Stump Grinder Teeth

Quadco Equipment inc.



But, this could work... I had envisioned a large wheel and nasty teeth but no reason not to explore this direction as well...

Carl

 

[J_J]

Surplus Center Item Detail

My tractor is rated at 3200PSI and 18GPM... I am still learning about how hydraulics work and how this would fit into my system so I ask because I am sure I am missing something important... Have yet to figure out all the logistics, but the stump grinder that fits my tractor is $1900 so I think I can build it cheaper...

Carl, I don't think that motor will stand up to the loads involved. That shaft is only 5/8 in, and if you connect it to a 20 or 30 lb wheel with blades, I think it will twist the shaft off, or burst the aluminum case. The motor on my PT trencher/stump grinder, probably weighs 30 lbs, and has a 1 1/4 in shaft, driven directly.

I have some of those Rayco carbide teeth. The local stump grinder distributor has these teeth in stock, and he will also sharpen worn teeth. I was thinking of building up a new blade and teeth configuration, because the teeth on the trencher/stump grinder are fixed, some straight and others off set.

 

[woodlandfarms]

So JJ. You agree with John that isolating the motor from the blade would be better thing than direct drive like the PT?

Carl

 

[sandman2234]

J_J,
What do you think about using extra drive motors from the Steiner,($$) or maybe those on that Jacobson reel mower that I have for parts? Seems like the Jacobson wheel drive motors would work, but I don't think the reel drive motors from that same mower would have enough hp.
Carl,
I have an Jacobson LF-128 reel mower that I bought for parts, but missed bidding on the "running" one due to the auction ending before I got my bid in. Depending on freight, and what it takes to get one or both of them out, it might be worth looking into. However, used ones might be found nearby due to their being at least one golf coarse or two in your area. It is something to think about. Steiner parts are never cheap, so I figure those won't be of interest to you.
One of these days I am going to pull the Jacobson apart and put the pieces on ebay. If you think you might be interested, it will just be a good reason for me to start.
David from jax

 

[sandman2234]

Since the wheel really doesn't matter, it is the cutting teeth that do all the work, you could take a large sprocket from some sort of machinery, found in a local junk yard, and lay out the cutting teeth carefully on it. Then drill and bolt the teeth on it. If you get the shaft that the sprocket is mounted to while your in the junkyard, you can buy some pillow block bearing for it, and a small pulley to drive it. I like the belt drive option, so looking for a piece of machinery with a chain drive pulley mounted on a shaft might be one way to go. My trencher/stump grinder is a wheel mounted directly on the shaft of a gearbox with a taper-loc bushing. The wheel already had one in it, I just had to buy the right bushing for the shaft I had.
Course, you can always go spend some money buying the stuff new, but some of the junk makes good "new" parts.
David from jax

 

[JohninCT]

If a large heavy wheel with big carbide cutters is what you're after, I'm with David... a trip to the salvage yard might turn up something usable at a reasonable price. The cutter wheels on the web sites you posted are awesome, but I'll bet their price is too. Also, as JJ said that smaller hyd motor would not be suited to a large heavy cutter wheel. So, you would need to look for a hyd motor a little more substantial.