Stump grinder project - need some input

[Jim Timber]

Looks like I might get back to working on the grinder this week.

That Greenwheel looks really hard on the driving engine to me. Going from unloaded to momentarily loaded every 180 degrees has to put vibration into the machine something fierce. I can't imagine most grinders are set up to handle that kind of impulse and I'd venture stress cracks might become a common theme on those who've adopted the system. Maybe I'm just paranoid?

My tooth spacing will be 3 sets of 4 teeth (24 total) spaced so that there's a swath cut every 120 degrees through all the tooth planes. I haven't laid out the pattern on the wheel yet, but it should keep more than 2 teeth in the wood at all times on most stumps.

I have to keep myself in check to some degree too. I come from metalworking now (been 20 years since I did much other than framing with wood), and metal is far less forgiving and needs a lot more rigidity in the setup or bad things happen. Chunking out a stump isn't precision work and it doesn't really matter if you tear out the workpiece or make a smooth cut - as long as it's gone.

 

[woodlandfarms]

Jim... I don't know how I missed this but you have seen my build, right?

http://www.tractorbynet.com/forums/...mp-grinder-build.html?highlight=stump+grinder

Happy to share notes. My system has a 22" wheel with 16 teeth total (8 on each side). But I spaced them per GreenTeeth. I do not notice any vibration and they are not spaced around the rim identically.

 

[Jim Timber]

I hadn't seen yours since the search engine doesn't work here and google comes up with all kinds of stuff from everywhere when you use it without doing the site specific search (which I never do).

Looks like you came up with a really nice grinder! How's it holding up after being shoved in the dirt as a trencher?

What tooth offset did you go with when adding the additional teeth at 30 degrees to the 90's? I've been thinking of going just over the tooth diameter for center-to-center spacing on the greenteeth (700's just like you used). That'll give me about 2" of cutting width give or take on either side of the wheel.

I'm also torn on the cutter RPM issue. I can speed it up and lose torque, but gain inertia. JJ was hung up on torque with your build, but required torque is determined by applied load and that's operator/technique dependent as much as anything. If it wasn't, a 8hp stump grinder wouldn't work, and we all know they're available for rent at just about any hardware store (by the hour - those greedy basxxxx's are smart! :laughing: ).

I should also mention that I'll be adding a motor valve on the drive circuit for this so that the rear SCV won't see any pressure rise from turning the motor off. I had thought that maybe I could get away with dropping it down into regen to decel after/between stumps, but it's only $90 to put the right valve in the circuit and bungee the SCV when the grinder is attached.

I'm also going for a flat screen and a remote camera. It'll help with lining up on stumps, and will be an asset for doing loader work with the forks as well.

 

[Old Junk Man]

Ive got a big ole stump grinder. it has a large 3 ft grinding wheel. and the wheel is driven by the tractor pto. it has two cyls that slide it into the stump. it hooks to a three point lift. takes a big high Hp tractor to power it. I was thinking of mounting a 4 cyl engine on it to power the grinding wheel and use any three point tractor that has hyd remotes. llI try and get some pictures. Its from way back in the day when they cut the timber with a stump saw and ground the stumps . they used them to clear rice field land.

 

[woodlandfarms]

On the wheel, Lets call the teeth pairs (there is one on each side).

I have 4 pairs 90 degrees from each other.

I then have the remaining 4 offset 30 degrees on either side of one of the 90's. So.... 3 whacks, a whack, 3 whacks, a whack is what happens when it spins. My wheel is 1/2" thick steel.

My 90 degree teeth (If I remember correctly) I have 2 pair that are straight, and the rest are offsets (maybe 4 pair are straight but I don't think so). The rest are I think 1/2 inch stepped down the wheel from the straight. (meaning each tooth moves a 1/2 " closer to the wheel hub)

The people at Greenteeth are SUPER Helpful. Give them a call. Really. Every person I talked to said "You are making your own?" Greenteeth said "let us help, its easy".

Speed is the key. Torque is secondary IMO. You want the thing spinning like a saw blade. 900 RPM for Hydraulic.

As for how it has held up. So much better than I could have expected. I am honestly stunned at how good it works. Huge smile on my face. And the trencher is way cool. We do not have a lot of rock, but dirt is abbrasive (and so are the mystery metals that my property has buried just under the surface like fence posts and car parts).

When I get back home, I will rotate the greenteeth. The ones on the straight arm finally showed some wear after the near mile of trenching I did. Greenteeth have 3 cutting sides on them. So you get quite a bit of use out of them before you sharpen (which, while they say is easy, looks hard as heck to me).

Happy to advise however I can.

 

[Jim Timber]

Just to close this up - I ended up abandoning the hydraulic motor idea for lack of flow and how it would've needed to be run so the sweep even worked. I'm glad I did.

I'm not sure on stump count so far, but it's probably close to or exceeding 50.

So here's a little video of the machine in action.

https://youtu.be/84kD27uKFy8

 

[farm boy00]

Just to close this up - I ended up abandoning the hydraulic motor idea for lack of flow and how it would've needed to be run so the sweep even worked. I'm glad I did.

I'm not sure on stump count so far, but it's probably close to or exceeding 50.

So here's a little video of the machine in action.

https://youtu.be/84kD27uKFy8

Like it but I would be concerned about the chips going everywhere. Maybe extending the sheild??

 

[Jim Timber]

I have a chunk of rubber to add, but I haven't bothered to yet. The operator is quite safe behind steel in use, and I'm grinding stumps on a road construction project deep inside my property.

 

[woodlandfarms]

Can we get some detail pix of your build? Looks great. Sorry you abandoned Hydraulic but totally get it if you don't have the flow.

 

[Jim Timber]

I'll put more up later. It's just a 83hp 1.46:1 Omni gearbox with the vent plug removed (I talked to an applications engineer at Omni about running it on it's side). Then other than the greenteeth, pillow blocks, and cylinders, I built the rest.