Stump grinder project - need some input

[Jim Timber]

I've got a hydraulic motor I'm not going to use for a skidding winch after all, and I just bought a 21x3/4" steel disc for my wheel (76#). I'm going for a loader mounted unit (SSQA) and will run the motor off the rear remote via bungee and will use my 3rd function to swing the arm. It's pretty easy building/designing to this point - but what I don't know is how many teeth I should use?

I can get Greenteeth and pockets locally for a reasonable price, so I think that's the route I'm going to go. The salesman at CEI said he didn't think the 500's would handle the hydraulic power and to go with 700's at a minimum, claiming 500's would explode. I'm used to 3 teeth in the cut at all times from machining, but is there any rule with stump cutting? Lots of the smaller machines have 4 sets of teeth 90 out from each other. Larger pro grinders use double that and up. How do you determine when you're just wasting money on more teeth?

I'm also torn on if I should have it pulling the cut towards the tractor or throwing the chips away? Seems like it'd be easier to see if it was throwing them out, and less chances of getting a rock chucked back at the tractor, but there's merit in not putting that torque down on the loader arms.

Thoughts?

 

[whis]

more teeth less vibration, no way I would put a stump grinder on a loader it will shake it to death

 

[Jim Timber]

Even if you put the weight of the tractor on it and anchor it down on the ground?

I'm envisioning round "feet" on the bottom of the SSQA plate so it makes a pad that the angle can be rotated around for depth control.

Foggy brought his tractor and 3pt Woods DG50 grinder over to do a stump for me, and that thing bounced all over from lack of down pressure on the hitch.

 

[Jim Timber]

This is what I want to avoid building

 

[whis]

that won't last very long before it falls to pieces, not spinning near fast enough, not enough teeth, and no way shape form or fashion strong enough. look a some commerical grinders for idea's. you can make it work but i would try to buy before building one they take a lot of abuse

 

[Jim Timber]

That thing's a joke.

Geared up (via double v-belts) I should be around 1k rpm with 68ft-lbs torque.

I got 24 green, Greenteeth 700's, 6 straight pockets, 18 angle pockets, and the appropriate screws today. I'll be working on making the grinder next week when I'm in the shop. I'll be cascading the teeth around the sides of the wheel to keep fresh cutting edges in the wood similar to their reverse-s wheel. The rest will be built stout with the expectation of being leveraged off dirt to make a stable platform and reduce loading the loader in the cut.

 

[whis]

good luck post a pic

 

[BigRol]

Man that scared the **** out me just watching the video!

 

[Jim Timber]

Man that scared the **** out me just watching the video!

That dumba$$ sells those on ebay! I half feel bad for his victims, and the other half thinks stupidity should be painful...

With the speed/torque calculations, I should be right around what a gas 25hp grinder would deliver.

I need to double check my v-belt idea to make sure the belts can handle it. I may need to run more of them for the power. I like belts over chain/gears because they can slip if I find something really solid.

 

[Renze]

that won't last very long before it falls to pieces, not spinning near fast enough, not enough teeth, and no way shape form or fashion strong enough. look a some commerical grinders for idea's. you can make it work but i would try to buy before building one they take a lot of abuse

Just look at the wheel wobble !! I bet one tooth protrudes more than the other and that, together with not enough rotational energy (low rpm) is whats causing the jumpiness. But an orbit motor is suitable for this kind of abuse because it has strong axial and radial shaft load ratings.
The Greenteeth wheel only has six teeth but it works remarkably good: