Trencher and poorboys stump grinder

sandman2234 · Dec 25, 2005

Many years ago, I built a trencher to keep from having to spend $40 to rent a trencher. Although the design has a few flaws, it works rather well considering who built it. On one of the first trips thru the backyard, it encountered a buried concrete block that previous owner had tossed into a hole to stop his dogs from digging. Never even slowed down the 13hp Ford 1100 I had pulling it. I found it when I went to lay the pipe. Later I needed to dig up a stump, and used it to cut the roots, but got carried away and did the whole stump.
The teeth are 1/2" by 3" flatbar, with stellite hard surfacing rods welded back and forth across the face.
Lately I have had a rash of shear pin failure, but have decided that the teeth might need sharpening. (and straightening the bent ones).
One to one gearbox, capable of digging about 11" as setup, but with longer teeth, I can probably extend that to about 18". The Ford 1100 won't pull it any deeper than that, and haven't had a need to try it with the JD2555 I recently purchase.

Chain was just put on there to transport from the backyard, don't ask what the rope is doing.
David from jax

andrewj · Dec 25, 2005

can i have it? haha. very nice. I am always amazed by the stuff you guys create.

automech · Dec 25, 2005

nice job! what did you use as a gearbox? which way does it turn?

Jim_WV · Dec 25, 2005

Pretty neat looking attachment sandman , thanks for sharing /forums/images/graemlins/smile.gif

sandman2234 · Dec 25, 2005

Andrewj,
Guess I better hang onto it, but in reality, it is a very simple design. The 3/16" plate guard was the hardest part, and I had some excellent help with that from a company called Ray's Sheet Metal just north of Gainesville, Fl.
The gearbox is simply a 1:1 and the wheel throws the dirt at the back of the tractor, which was very interesting since I dug about 15 feet of trench without the guard, when I first built it. It was throwing a rooster tail 40 feet in the air, covering me and the tractor in seconds. Wish someone had taken a picture of that!
Here is a couple of pictures of a gearbox like the one on the trencher. It is a spare I got, in case I tear up the orignal one.
I also have a couple about the same size, or a little bigger that are 3 way boxes, meaning one imput and two outputs at right angles. I am still looking for something to use them for.

sandman2234 · Dec 25, 2005

Thanks for the kind words concerning the trencher. It was copied from a small trencher that was powered by a small gas engine, spinning a wheel about 8" in diameter. Not my design, but I made it from stuff I had. Only thing I have purchased is the drive shaft, and a handfull of shear pins.
The work on the guard was done as a favor and was a life savor. It wouldn't have been near as pretty if I had done the guard by myself.
David from jax
I think highly of Ray's Sheetmetal everytime I use it!

beenthere · Dec 25, 2005

Neat idea. Interested in what machine you salvaged this from.

From the pic, it looks to me like there is a pretty sharp angle where the PTO connects to the gearbox, that would be reduced if the top link was several inches longer (or the attachment point on top was moved several inches forward). As it is shown, doesn't look like it would reach the max depth with the shroud 'parallel' to the ground. Maybe just the way it's hooked up now.

For trenching those paddles look good. For stump grinding, more 'teeth' and some 'cutter' teeth (in line with the direction of rotation) like striking with an axe, followed by some 'rakers' across as they are shown. Just a thought as to how it might chew up wood better, and maybe the same arrangement would work for trenching too.

I like the concept and design.

sandman2234 · Dec 25, 2005

I agree that there are design flaws, especially for a stump grinder. However, it saved me $40 the first time I used it, and that was many years ago. (almost 20 years ago). I had never used a mill before, and was trying to learn as I went, on someone else's equipment.
I have a couple of bent teeth from it bouncing when it is cutting stumps. If all the teeth had been the same length, and about twice as many of them, and probably a little shorter for stump grinding, it would have been better.
It works pretty well as it is, so I just use it and don't worry about it.
If I don't get the shear pin problem fixed by sharpening the teeth, I may go for a design change, since I have my own milling machine now.

As far as the machine I salvaged this from... well none really.
The gearboxes were part of a wharehouse full of parts a friend purchased. I got involved in helping him remove them from the wharehouse, and dispose of a lot of it. He made some serious money on it, and I got to pick and chose a lot of the parts I have used over the last 20 years.
The frame for the trencher is simply channel iron, 6" I think, without going outside and measuring it. Gearbox mounts underneath, and has a QD type taperlock bushing holding it to the shaft. The wheel is just a turnaround wheel from some cable pivot point, part of that wharehouse of stuff.
I actually have a couple of gearboxes, and one more pivot wheel, so all I would need to build another is a taper lock bushing, a driveshaft, to build another.
If I ever do, I will use 3/4" plate for the teeth, to give them more strength. Probably send them out for heat treating, instead of using stellite hard surfacing rods.

You are correct about the top link being too short. I merely hooked it to the JD2555 to transport it. I usually use the Ford 1100 to drive it, although it is almost more than the little tractor wants. I need to invest in a long top link, because the flail mower needs one also.

David from jax

gotrocks · Dec 26, 2005

Man, that is a great looking attachment.
It dosen't look it's age. /forums/images/graemlins/grin.gif
I have been wanting to see something like that.
Can you tell me what ratio most brush hog gear boxes have?
Do you think higher than 1:1 would work on that type use?
Of course the dia of the working blade would have some bearing on the final performance. Thanks for a little disertation/speculation on this.
<font color="blue">Happy New Year </font>

sandman2234 · Dec 26, 2005

Another use for this spinning wheel was considered. Since it has those holes in it, I thought about cutting a 4" hole in the side of the guard, and welding a short pipe on it. Then making some blades to bolt to the side of the wheel over those holes. That would make a way to get rid of sticks and limbs, by making them into chips/sawdust.
I guess if I ever need it, I can do it. Right now, a friend gets all of them to burn to heat his house, so it isn't an issue. Just a thought for someone not able to burn, etc.
David from jax

sandman2234 · Dec 26, 2005

It wouldn't look it's age if I had painted it, or stored it inside...but I didn't, so it really does. Thankfully it was made out of serious metal, so it hasn't rusted away yet.

I really didn't know how this thing would perform as I built it, but I figured I could change the length of the teeth (which is why there is so much clearance on the guard, or I could shorten them, or if need be, even narrow them up. I built it to lay sprinkler system pipe so the 3" is really too wide if your doing it for a living. (I'm not)
Horsepower and shock are the critical factors. I used it on my last place, which had a lot of sand, so it was fine, but on harder packed dirt, it needs some help (Note that it has always been pulled by a 13hp Ford 1100) Now that I have the John Deere, I am waiting for another project to try it out on. Have considered a yardlight in the front yard, but I don't know where my phone lines are at, so need to have them located first. Plus it really isn't a pressing idea with street lights.
1:1 ratio gives a pretty fast speed, but not too fast. Any less than that can be adjusted by the diameter of the wheel. The bigger the wheel, the more HP, and faster surface speed at the tip of the blade. Calculations of the speed of the blade tips are really not that hard to figure. I can calculate the blade tip speed if anyone really needs it. Most of the guys here with the monster tractors (compared to the 13HP) will be able to pretty much do what they want. However, larger wheels will probably eat hp up pretty fast, so don't over do it, just to get the depth. Curved blades, or angle blades will probably help reduce the hp consumption. Narrow blades will also help for the people with compact tractors. A flat shaped discs or flatbar, like a garden tiller uses, riding behind the trencher would probably help to keep it in line if your 3pt has much play side to side. Might complicate making turns, so taking the slack out of your 3pt might be easier.
Stump grinding is something this thing manages to do, but in this setup, it doesn't do it well. With sharp teeth, it will eat a 3" hole right thru a solid stump, but as light as it is, it requires a light touch on the lift handle to slowly feed it as it cuts. Precision during blade manufacture would probably have been a good thing, as mine were different lengths when I installed them. (remember 1st milling machine project).Side to side slack in the 3pt hitch also becomes a very noticable factor. The best way would be to able to control the slack as movement, but that takes some designs I didn't want to tackle. An increase in the number of teeth, and a little shorter would be good if your planning on doing much stump work. Roots under ground don't seem to effect this, probably due to the angle of pull when lowered.
I have also considered turning the wheel at a slight angle to clean out existing ditches, and to make new ones to control water runoff around my place. An angle would allow it to dig a half moon shaped ditch.
Anyone with a post hole digger gearbox that wants to trade for one of my spare 1:1 gearboxes, feel free to contact me. One of my next projects is a posthole digger.
Any questions, just ask.
David from jax

3RRL · Dec 26, 2005

David,
I don't have a PHD gear box to trade but I'm interested in buying one or two of your gear boxes. Send me a PM if you're interested.
Thanks,

sandman2234 · Dec 26, 2005

Rob,
I will consider it after I have located a PHD gearbox, or given up and bought the whole thing. It isn't really high on the priority list so I won't be in a big hurry.
I have also considered building another one of these, and trading it for a complete PHD, or something. I really only need a PHD for a half dozen holes in the 12" diameter range, to set some powerline poles so I can throw up a pole barn.
Trust me, I have way too many projects for anyone of them to get in too big a hurry.
David from jax

sandman2234 · Dec 26, 2005

A little closer to you, and for sale...

ebay link

David from jax

<font color="red">EDIT shortened long link </font>

3RRL · Dec 26, 2005

Alright David,
I'll email the sellor and ask if he knows the HP input rating for it.
Thanks for the link.

sandman2234 · Dec 26, 2005

Rob,
Your welcome on the link. Good luck, because the seller doesn't even know for sure who makes it. I suspect the PTO hp of your tractor will be more than mine also, if you come down to rated spec's. I never called to find out what my gearboxes are rated at.

For anyone wanting to know what the diameter of the wheel at the blade tips is, I just measured it.
28 inches tip to tip, 540 rpm is what it has always been run at, blade tip speed should be easy to figure.
David from jax

rambler · Dec 27, 2005

To me these look like generic right angle 1:1 gearcases used on grain augers. Pretty common stuf in the ag world. With any markings and a good supplier catalog, can likely get the hp ratings of them.

That 'possibly IH' unit probably is not. There used to be a common gearcase with pto shaft & slipclutch that came fro the IHC mounted cornpickers. They had one input, 2 output shafts - not a single output.

--->Paul

gabby · Dec 27, 2005

Cool. How much of the dirt falls back in the trench?
gabby

sandman2234 · Dec 27, 2005

Gabby,
More than I like, but it is pulverized to a point that it comes out very easily. It depends on the depth that you are trenching, for several reasons. The guard is wider than the blade, so dirt hitting the guard falls next to the trench, but if your trenching too deep, it builds up in excess and falls into the trench. Deep trenching also lowers the guard, so it knocks some of the dirt back into the hole also.
Although a pain, scooping the pulverized dirt out is a whole lot easier than taking a shovel and digging the trench by hand if you know what I mean.
I have actually dug trenches 10" deep, to bury a pipe 6" so I wouldn't have to scoop any of the dirt out. Yeah, call me lazy if you want...
I have considered putting a semi circle shaped scoop right behind the wheel, as part of the guard, to keep the dirt out, but like a Post hole digger, you only use it so much, so why spend the extra time designing and building when it works ok?
(Now if I could save another $40, I might have a reason!LOL)
Tooth configuration is probably the easiest way to solve the dirt problem, along with acess in the guard to get rid of it.
David from jax