Stump Grinder for a 425

[jfischer]

I know from reading on here that I probably shouldn't do it, but I was trying to dig some stumps out this week, and after digging 4' down all around them, cutting roots as big as 8-10" and "Think" I got all them cut, the stumps would still not budge.

SO, I have decided to try one of the PT Stump grinders. I have at least 15 or so stumps that I know of that need grinding down below the ground here, (and I am sure I will find new friends wanting me to grind theirs) maybe a few bucks can be made with it.

They say the new one has bolt on teeth, and maybe it works better then some in the past, or the video I have seen with it with the guy that looks like he has no idea of what he is doing.

Any others tried the newer grinders on the 425 series?

Can't be any worse then the videos I have watched with people renting them from Home Depot, some of those are pretty funny, and the people are just beating the machine to death.

 

[woodlandfarms]

I built my own, Much cheaper

 

[KentT]

I have a stump grinder with bolt-on teeth. Like most PT implements, it does a decent job once you've learned how to use it - which the person in the PT YouTube video clearly had not. It doesn't have a lot of torque, so it is easy to take too big a bite, and bog it down.

It doesn't compare to a dedicated, specialized stumpgrinder like you can rent, but does a decent job. Note that several of us have reversed the blade and hoses so that it throws the chips away from you....

 

[jfischer]

Thanks Kent for the response. I kind of figured it didn't have much torque to it, but I wonder if some of that has to do with the skinny disc, as most seem to have some mass to them, and seems once they get to spinning it looks like that helps out, but I would assume with only being held on the one side, without bearings on both, it would come apart if the blade was very heavy.

How long do you get on the teeth, before they need to be sharpened, and does it help to keep it out of the dirt like a chainsaw?

I saw where a lot were making it run in reverse, I wonder if it had any rubber skirting along the bottom like most stump grinders have on them if that would help?

 

[KentT]

Still on the original set of carbide teeth - they don't wear fast at all. The teeth are pretty substantial, and that combined with all their mounting bolts, makes the whole blade surprisingly hefty.

You don't have to be concerned about contacting the ground - I typically grind stumps down below ground level. I've ground the tops off a couple exposed veins of rock in my yard with it. Others here have cut asphalt with theirs. Those teeth are tough, and most homeowners would likely never need to replace them...

 

[J_J]

They can also be sharpened with a green stone.

My stump grinder is also used for trenching.

The teeth on mine are the braze on kind.

Some of these guys have larger machines with more flow and available HP.

I consider my stump grinder pitiful.

On softwood, just marginal . Hardwood, just bounces. Every once a while, it throws a chip back.

 

[jfischer]

Thanks Kent, I kind of figured that the teeth might be kind of hard. Knowing that it doesn't have many GPM with the machine, have you noticed that going slow, and trying to keep the RPM steady in the mid to higher range seems to help any. I know this machine is sure hungry for gas

I should go down Monday and pick it up, and will give it a try. I have stumps from the rotten stage, to some I cut about Nov. of this last year, so I should be able to give a good test on them.

I thought about turning it backwards like I have seen a bunch are doing, but not sure it will be big enough to reach across a few of the stumps I have. The mini hoe would barely go across when I was trying to chip away the bark on the outside of some stumps, but I had already dug about 4 foot down all around them to cut the roots.

Still on the original set of carbide teeth - they don't wear fast at all. The teeth are pretty substantial, and that combined with all their mounting bolts, makes the whole blade surprisingly hefty.

You don't have to be concerned about contacting the ground - I typically grind stumps down below ground level. I've ground the tops off a couple exposed veins of rock in my yard with it. Others here have cut asphalt with theirs. Those teeth are tough, and most homeowners would likely never need to replace them...

 

[jfischer]

JJ, I have one of the Baldor sharpeners I sharpen milling bits on, and it does a pretty good job on the carbide on them.

I have watched a lot of videos on the grinders, and think that the one for the 425 only goes maybe 800 rpm tops. Seems some of the smaller ones are really zinging the rpm, and have small cutter heads on them, not that the 18" on the PT one is very big, but big enough for the small amount of fluid that is going through it, maybe too big with only 8gpm.

Is your grinder a PT one with the 24" disc on it?

 

[J_J]

It is either 24 or 26 in .

It is one of the early 90's trencher/stump grinder.

 

[jfischer]

Went down Monday and picked the stump grinder up (and a box blade also, even though I know it will not do real hard surfaces) but I was down there, and it saved on shipping.

Well, I tried the grinder, and do have to say that it worked, but not very good in my opinion, (the machine, along with me and everything on it was loaded with chips) but knew that before I started. So, that evening decided to reverse the disc like others have talked about on here. I can tell that they know people are doing it now, as the disc has a taper on both sides now, (unlike what i have read other found on the older grinders). I changed the quick connects on the hoses first to reverse the motor, but found that the hoses are different lengths, about 10" longer on one side, and when you curl the grinder forward the one hose that has been switched to the left of the machine gets REAL tight, so I unscrewed the hoses out of the hydro motor for the grinder to reverse the flow. That was fine, but with the 1/2" hose it has such a tight angle to try to screw it back in I had to end up taking all apart to be able to screw the hose back into the motor.

Decided to go out yesterday morning to see how it did, and actually worked pretty good. Had nice chips coming off it, and just need to learn to feed it side to side, and get the feel when you are trying to take too much off at a time, and just go in reverse with the machine to drag across the stump.

Over all for the price I don't think it is that bad of a purchase if you have a few stumps to do, and don't want to rent a machine, and just take your time and do them when you have a free moment.