Stump grinder project - need some input

[Jim Timber]

Those of course started as bar stock before being turned.

Frame taking shape

Dry cut saw doing one thing it does really well

I use a temporary pin to hold things in alignment for welding

This is a different view of the hub flange before being assembled to the splined sleeve

That's pretty much it for build pics.

 

[woodlandfarms]

Very impressed. More questions to come

 

[Jim Timber]

Stump grinder via trail camera - YouTube

 

[Reg]

Stump grinder via trail camera - YouTube

IMO that video demonstrates vertical bounce caused by trying to cut too "vertically".
My preference is to cut DOWN into the stump, I probably take more levels and reposition the tractor more than most people do, but I only cut with the blade in the wood between about 5 and 7 o'clock - nowhere near the 8 and 9 or 4 and 3.
{For those who still remember analogue clock faces}

 

[Jim Timber]

Reg, that video shows a healthy depth of cut (around 2" per pass) in a stump that covers from 4 to 9 o'clock (or better) in some areas. The "bounce" is fine with me. I have hundreds of stumps to grind, so I'm putting my 50+ PTO ponies in the wood is how I plan on making that happen.

 

[Reg]

Sure, I know and agree with the "more tool in the material" principle (-:

It may just be a personal choice and local conditions vary a LOT.
For what I have ground here with what I use and how I work (several variables right there).

I have found that TOO MUCH bounce can be a problem if/when the grinder hits a really hard spot on the way back down.
Clutch slip and/or stalling the tractor - - assuming I am already running close to max power I can put to it.

So my PREFERENCE is to avoid bounce, typically by limiting my cut to the bottom of the arc.
Sure, it takes a few more passes, but I'm not getting shaken to bits, I'm not breaking teeth, I'm not stalling the tractor, burning clutches, etc.
and when I get to a rock it is usually a light touch instead of hooking under it.

 

[Jim Timber]

I've been fortunate that I've only found smaller rocks thus far. That stump was causing hop because of how much of the wheel was in contact. I was down in the middle of a large stump, so the aft cutters were trying to lift while the fore were trying to pull down. You can see me stall the clutch in the video. If I run 300 rpm faster, it'll stall the engine (found that out in a bigger oak after adjusting the tension a little tighter) - so I think I've got a good "tune" on my twin disk clutch. The gearbox actually warms up slightly where it didn't where I had been running it. Hot clutches, and cold gears.

I wish I had some cutters deeper into the exposed side of the wheel for my aspen trees. Those are so soft, I could scrub them off in a couple passes if I didn't rub the wheel above the teeth.

 

[woodlandfarms]

I hit a steel culvert that was long since buried on the property with the stump grinder. One greentooth has a big chip in it now but I have not ordered a replacement (Just turned it over to the next sharper side). Have not hit much more than a 4" rock that I know of but it didn't stop the machine.