Stump Grinder Questions!

sandman2234 · Dec 26, 2008

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 · Dec 27, 2008

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 · Dec 27, 2008

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 · Dec 28, 2008

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 · Dec 28, 2008

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 · Dec 29, 2008

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 · Dec 30, 2008

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 · Dec 30, 2008

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 · Dec 30, 2008

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 · Dec 31, 2008

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.