How can I build a walk behind ground trencher? This is what I have so far.

[apples017]

I need to cut some trenches in the ground about 1" wide to install some irrigation pipes. Well 3/4" would do the job.

So I have a 2hp ariens tiller. It has a fair bit of power for what it is, considering that it has a total cutting/tilling width of about 12".

My idea was to remove the existing cutting arms/legs/bits and some how attach about 3 circular saw blades. The issue with this is that as it turns out the drive shaft is hexagonal. Good idea for transfer of power, but my circular saw blades have round holes not hex shaped holes. So what to do.....Maybe I can buy a cheap 16mm or 5/8" socket which will fit over the shaft. Then I might be able to weld the saw blades to that socket. Then I just pop in the bolt at the end of the shaft and presto it's done.

1. I don't know if you can weld a socket to a cutting saw blade with normal welding wire. Maybe I can TIG it????
2. The thing is geared down and will not spin at the engine rpm speed. The actual tiller arms spin slower that the motor.
3. If I can't weld a socket on, I was thinking there was these bracket thing that clamp the tiller arms on. They have little folded over bits of steel that insert into holes in the tiller arms the give extra grip. Maybe I can drill through a circular saw blade? then use these things to grip the blade for rotation?

That is what I was thinking along the lines of doing.
Then just before going in for the night, I saw that maybe I could have half of my tiller arms facing left then insert the spacer(bit of pipe) then the other half of the tiller arms would face right. So by facing each other, the total width of a trench would be say 2-3".

I think this idea should work, I mean it tills the ground the way it was built to do it. All I am doing here is re arranging the cutting blades. I will try it out tomorrow, fingers crossed.

But , if that does not work, what about my idea of using the circular saw blades.

Another issue is that with those saw blades I estimate a depth of only about 2.5". Hardly deep enough in my opinion for irrigation pipe. So maybe I might have to weld up some flat bar or something that is much longer so it goes deeper in the soil. I could weld some hard facing rods to the cutting edge of the mild steel parts.

Or another option could be for me to build a single point ripper tine and scratch it into the ground with it attached to the ride on mower , (read: not a garden tractor). I'd probably have to do a few laps around the place to get it down deep enough, maybe 1" deep at a time.

What are some thoughts on this guys and gals?

 

[Brad_Blazer]

I would try the tines bolted together with the blades flaring out in both directions. Sharpen the blades. Any space between blades will quickly get clogged with grass and roots. You could just take one outer tine set and move it as close to the middle as possible.

 

[apples017]

Yeah, good thinking 99. The grass probably will get all stuck between the blades facing each other, especially if I use three and three. I will do some experiments, back to back facing away, then facing in, then more blades etc. Should be interesting.

 

[BHD]

If you have a tractor, and have a yard that is open one can use a single shank and pull in the pipe, 81911 - Wire Mesh Grips

I have used a thin knife, (old wore out anhydrous knife) and welded a chain link on the back of it and we pulled in pipe for the church lawn I have pulled lines under gravel roads for putting eclectic fence in, and even done with the lawn tractor about all the digging we ended up doing was at the valve box and were the saddles went on,

yes the vibrating knives the pros use is nice, but if you have some traction and power, and your not to many roots, you do not need it,

we just used a small tool bar with one shank, went about 8 to 10 inches deep the way I recall, I still have the pipe pulling grip,

you will need some one to feed the pipe as you pull it, or get it strung out behind the path to be pulled,

(If the trencher is the way you end up going I would think you would want a lager disk so one could go deeper, http://www.tractorbynet.com/forums/build-yourself/260392-homemade-trencher.html

I would think just a disk with some tabs welded to it for teeth would work, but I could see it getting away from a person if not real careful, being on a light small machine like that,

It have been years but I did see one unit that was small and light, that was winched forward so it was anchored and the digger was pulling against the winch line,

 

[jwmorris]

I built this plow to install drip line but it would work for flexible tubing of any sort.

2hp would be fine for an edger but won't make a good trencher.

If you want 2-3" width you will be time and money ahead to just go rent one. If you want to use it intermittently until your finally finished buy one off of Craigslist and sell it when your done. If your in North Texas I have one I can make you a deal on because that's what I did.

 

[JohninCT]

Maybe you could get a hub like this.
Fholb-1 Fabricated Hub W/Bushings To Fit 1''Axle 4 Bolt

Lock it onto you hex shaft with set screws drilled and tapped into the hub.

Then bolt on two of these to do the ripping of the trench.
Box Blade, Ripper Teeth, Box Scraper | Agri Supply, 49684, Box Blade Shank

 

[apples017]

Yeah, no tractor guys

 

[Chemguy]

This thread might be of interest to you: http://www.tractorbynet.com/forums/attachments/18287-ever-try-trencing-roto-tiller.html

 

[lloyd430]

You can stick/wire weld sockets, I do it all the time, but realize it does make them a little weaker. Its better to insert the socket into a hole then weld it into place, rather than butt welding to another piece.

 

[apples017]

Yeah I pushed the socket onto the shaft then put the disc and hub over that. The spark plug socket was a perfect sliding fit inside the hole for the hub, so I did not have to grind it down to fit inside. It's great when stuff just works hey.

So it is up an operational, i also welded on 4 bits of flat bar about 2"x4" long and say 1/4" thick. To this is welded on some hard facing rods and ground them to a knife edge. LOL, it works, in the areas where there is green grass the cutting disc will go right down to max depth in a few seconds. Anywhere the grass is green obviously there is more moisture there and it really works like a proper engineered machine. But on harder soil that is dry, it still works but takes a lot longer to scratch through the dirt. Ideally a heaver steel frame, a larger motor and faster spinning cutters would be better, but given what I had it is not to shabby.

Certainly beats the **** out of using a pick and shovel that's for sure.

One thing was that welding those bits of mild steel to the mower disc plate I got lots of porosity. I imagine that the mower disc is a different metal....The socket welded funny too, but I think it was not the socket itself but rather the mower steel.