Stump Grinder Questions!

[Scotty370]

I want to build a 3 Point hitch Stump Grinder Attachment patterned after several after market units out there for my John Deere 4200. (26hp 3cyl Diesel w/ Backhoe/Bucket). Two immediate questions: What is the cutter wheel rotation suppose to be? I say lower teeth should be moving toward the tractor. Thus if your standing on the right side of the machine it would turn counter clockwise! The PTO turns counterclockwise (Doesn't it?) thus a right angled gearbox mounted on the left hand side would cause it to turn as described! This would cause the tractor to be pulled toward the stump when cutting. I think that's safer than having it try to launch the tractor forward. Also, Wouldn't it relieve 'side pressure' bearing wear if I were to build it with a shaft mounted cutter wheel supported on both ends with pillow blocks? I would leave a splined end facing the gearbox that I could hook up with a Lovejoy type connector. (IE two internally splined metal hubs with a rubber insert. Also I need parts sources for the wheel if I don't 'tooth up' a piece of 1/2" plate. I'm thinking a 24" wheel! Any help appreciated! ~Scotty

 

[debushau]

I don't own one but there are videos of them on the Shaver website, Baumalight website and the Bobcat website and probably other places too. I figure you can probably see from there which direction the spin.

 

[RickB]

A lovejoy style coupling is your first mistake. You should use a solid coupling or a pair of sprockets and double strand chain coupling if you are worried about alignment. Shaver uses a solid coupling, I'm pretty sure.

 

[RedMahindra]

Youtube has videos on stump grinders.

 

[jimgerken]

I have seen a very large grinder work in my yard a few times. It's the dirtiest operation you ever want to be involved in. If there is a way you can direct all that dirt and wood/dirt combination stuff AWAY from the operator and the tractor and the tractor's air filter, you will be happier. Oh yea, and another thing: the machine shakes and jerks violently sometimes. Plan for that too, if you can.

 

[wedge40]

I just watched a video and the shaver rotates clockwise when standing on the right side of the tractor. Or it shoots the chips out the back. Never noticed before but they have a guard that deflects most of the chip to the ground so they aren't scattered all over the place. If you decide to continue this project please give us progress and photos.



Wedge

 

[daBear]

Getting the grinding wheel to turn is going to be a project in itself. But the hydraulics to move it in and out and back and forth will be a bridge to far for most do it yourselfers. Probably one of the most complicated projects you could tackle.

 

[trrjohn]

Here's a picture of mine.
Grinder cuts down on the stump. Or counter-clockwise as you are looking at it. Cutter wheel is about 20" in dia - 3/4" plate and has 9 sets of carbide teeth. John

 

[trrjohn]

A larger picture

 

[Scotty370]

Thanks folks! I'm getting closer to a 'sit-down' at the drawing board! Looks like most of the commercial stand alone machines such as John's cut the chips toward the machine. I'm thinking it's safer on a 3-point hitch rig to have it throw the chips (stones, etc!) rearward. That will work, as I believe that my 540PTO turns clockwise (as you look at it from the rear of the tractor on my JD. (Can anyone confirm this? The tractor's at my summer place 50 miles away!) Thus, when the shaft goes to the 1:1.5 gearbox, and a shaft to the cutter, it will be throwing chips and debris to the back Was going to buy a wheel, but I've found teeth I can use at Greenteeth.com that I can mount on a 1/2inch plate wheel that I'll cutout. Now I have to figure out how to mount the tooth pockets as far as spacing goes! I'll be using 18 teeth, that mount in two's, at 9 locations. Thus, they'll be at 40 degrees between each pocket location. The problem arises because on the machines I'm trying to mimic, some of the teeth appear to be mounted closer to the hub than others! Darned if I can find a picture of a replacement wheel on the net that I can 'cheat' from!!! Thanks in advance for all input! ~Scotty

 

[sandman2234]

Ok, I don't have a lot of experience in this field, but I do have one that I built. I think the post was titled something like poor boys stump grinder or trencher. I also don't have a lot of time right now, but wanted to mention a few things.
Best way is for the wheel to throw the chips towards the tractor. Reason is, the motion of the wheel keeps a tension on the 3 point hitch, which keeps the items from having too much slack, allowing too much movement. I used a 3/16" thick steel guard (Thanks to Ray's Sheet Metal) which protects me and mine and keeps stuff contained within reason.
I think the measurements of the wheel is listed in my post of a couple years ago.
Blades were homemade, my first ever design, and first time using a horizontal milling machine, so they had problems. Due to the lower speed of a tractor pto, balance of the wheel isn't as critical, unless I got lucky, which I doubt. Still take extreme care laying out the cutters, as it will improve the cutter and reduce bouncing.
Hopefully I can take some time to follow this posting, but feel free to email or pm me if you think I can be of any help.

http://www.tractorbynet.com/forums/attachments/71073-trencher-poorboys-stump-grinder.html

There are several informative posts on stump grinders in the past, so do some searching to find them.
David from jax

 

[trrjohn]

My stump cutter has straight teeth, left hand and right hand bent shank teeth. Basically machine tool carbide cutting tools.

mounted like this

1- two straight
2- rt and str
3- lft & str
4- rt & lft
6- lft & rt
7- str & lft
8- str & rt
9- lft & rt

John

 

[David Devuono]

When standing behind the tractor, looking towards the tractor the PTO spins clockwise. Sitting on the tractor seat looking back, its spining counter clockwise.

 

[sandman2234]

The direction of pto movement is different on a few tractors. A B6000 sitting in the front yard is opposite from the rest of my tractors, or any I have owned. A constant battle when looking for pto driven attachments. All of the attachments the owner has are modified units, such as the finish mower I used with it yesterday. Not an impossible hurdle, but definitely a challenging one.
David from jax

 

[Scotty370]

David- Thanks for checking back in. I've got a John Deere 4200 Compact tractor, and I'm quite sure my PTO turns clockwise as I look at the tractors butt! David sort of confirms that. Thats the premise that I'm building on. Finally started today to put pen to paper and do a parts source/cost. I'm downsizing a little from a couple units that are out their and taking ideas from machines like Worksaver, Shaver, Woods etc. I've settled on a 22" wheel that I'll cut from 1/2" steel plate. Planning on buying a 40hp gearbox that has a PTO splined input that I can get at Agrisupply for $99-. Cutter teeth/pockets I plan to buy from Greenteeth.com or Bailey's. Their designed for a Rayco (1625A Jr) grinder, and I can buy a full-set of 18 w/pockets and bolts for about $325-. Those are the 'big ticket' items. I'll have to buy a couple hydro-cylinders down the road, but with a trip to the scrapyard for some more steel plate, at least I'll be able to strike some arcs, and make some sparks! ~Scotty
PS- Mowing in January? Darn, Just got rid of last weeks 2 foot snowfall thank to 50 degrees and rain yesterday and 50mph wind today! ~S

 

[sandman2234]

The grass I mowed Saturday probably needed it last fall, but I needed to travel about 120 miles each way to get to it, and my JD is really quite a handful for my Chevy 1500 p/u, so I just borrowed the 'bota and did what needed to be done, and left the field for later.
Blade tip speed needs to be calculated, just to be sure your not flying low with those carbides. I used regular 1/2x3" flatbar, cut an angle on it, and welded some hard surface rods onto the face. Might be a way to save a few dollars during the startup phase of your grinder. If you have access to any scrap yards, or such, you might consider using a gear from a chain driven pulley, as they really don't need to be solid like a piece of plate, but they do need to be close to being balanced, to save the bearings in the gearbox/jackshaft.
I would think a gear about 20" would not be impossible to find, although it might be a challenge. Wire mills use them all the time, on strander machines to set the lay length to different dimensions.
How are you going to attach the pulley to the splined shaft? My gearbox is a smooth round shaft and I used QD type of pulley conectors.(not the normal QD meaning used around tractor forums)
David from jax
If you read my post on poorboys stump grinder, you already know all of this. I think I also mentioned that I built the durn thing about 20 years ago, lol.

 

[kthompson]

It would seem if you could find the bottom of a backhoe it would work to give you the back and forth movement needed and even the up and down if the boom was still there. How it might affect the pto access no idea. You also have the ability to use PTO driven hyd pump to run this and that might be a lot better. You could also look for a 3 pth mounted boom mower. I am sure there are bent up ones out there that have been scraped.

 

[Scotty370]

Ken- I thought of doing that, because I've got a backhoe for my 4200 Deere. I could probably have replaced the bucket with a fabrication to mount on the same pins, and powered it with a Hydro motor from a PTO mounted pump as you suggested. Problem that I envisioned is that a backhoe is a pretty 'sloppy' piece of equipment! By that I mean that even with the dipper tucked in close to the main boom, you can push it easily by hand back and forth, probably 3" in each direction. I'm thinking that I want somethin' rock solid before I drop an 800+rpm wheel into a stump! Thanks for your input! ~Scotty

 

[wldrbob]

hi could you build a mount for your backhoe that works like the 3 point winches that dig into the ground that would hold the stump grinder solid and your bucket cyl could run the wheel up and down you could maybe make the teeth a bit wider with the back hoe you have infinite adjustment anyways its a thought

 

[Taylortractornut]

Someone here a few years ago added a Powertrac stump grinder to his Magnatrac Backhoe. Ive run a large stump grinder on an excavator one time. And it wasnt a very new machine and it had som slop to it. The cutter ran aya from the scarrier and it held the sslack out of the machine. Ive seen a few home made stump grinders that had a wheel made from carbide bits and the the gear box drove it from a pulley set up to to reduce gear box shock and also gave it more RPM. The drive shaft to the pulley also had a pulley to run a pump the pump fed a valve body to run the lift and swing of the grinder. the whole unit had a blade like sat on a small blade shaped plate to dig in and hold the tractor. When the stump was done grinding you could raise the head then your 3 point and backfill the hole with the chips.