Thinking out loud

[rd_macgregor]

Many years ago I had a summer job in SoCal installing automatic sprinkler systems (mostly) in suburban yards. We used a machine about the size of a rototiller, except that it had a couple of long, L-shaped tines that did the digging. My recollection is that it made a ditch about 2" wide by 10-12" deep. We were working in soils with very few rocks, though.
I don't know if this ditching technology is still used.
BOB

 

[brokenot]

So what's the speed of a commercial machine and what's the blade size? Once you know that you can calc FPM at the teeth

That second video link I posted a couple of pages back mentioned a blade speed of 800 rpm. More details and photos on their website here:

Welcome to Little Beaver Inc., Earth Drills & Augers

The blade diameter isn't mentioned, but it will cut up to 12" deep, so with the height of the teeth included it's probably about 26"-28" across and the blade has 6 tooth stations on it.

Get your tooth tip FPM speed in the ballpark and you'll be set....

 

[Rob-D]

That second video link I posted a couple of pages back mentioned a blade speed of 800 rpm. More details and photos on their website here:

Welcome to Little Beaver Inc., Earth Drills & Augers

The blade diameter isn't mentioned, but it will cut up to 12" deep, so with the height of the teeth included it's probably about 26"-28" across and the blade has 6 tooth stations on it.

Get your tooth tip FPM speed in the ballpark and you'll be set....

It could be an interesting project. The teeth look like carbide inserts for lathes, probably C2 cemented carbides and relatively cheap. Although carbide doesn't do well on interupted cuts, I'd almost use HSS with maybe 5% cobalt. If you're not doing commercial work the teeth will most likely last a long time.

I'd say your estimate about the blade diameter is pretty close.

Rob

 

[handirifle]

OK I am liking the idea of the 3ph driven wheel digger. Seems I saw a gearbox online for like $149 or so. Wonder if I could get a used one somewhere for way less?

 

[smiley]

Check out junk farm machinery. I have a couple off manure spreaders in inventory for future projects. One cost $15, the other was free for taking it off.

 

[Treemonkey1000]

Do like they do with Post hole diggers and use the rear end from a truck.

 

[Rob-D]

I'm wondering if you can't run something like a middle buster or just a long 2" wide flat bar into the ground about 8 or 9 inches and drag it along.

Rob

 

[Oldstuff]

handirifle- in your opening post you indicated 3/4 or 1 inch pipe. I am no sprinkler expert but I do have a system and have had it for 28 years and have done all my own maintenance. I watched the installer put in my entire system and asked a lot of questions.
They recommend 1 in black poly for the main supply for residental applications. Some of the secondary pipes are 3/4 and a few that go to small heads are sometimes 1/2 inch. Make sure you understand pressure, volume and gallon per minute needs before you lay pipe.

 

[handirifle]

I'm wondering if you can't run something like a middle buster or just a long 2" wide flat bar into the ground about 8 or 9 inches and drag it along.

Rob

Yea probably could, just not nearly as exciting to think about.:thumbsup:

Oldstuf
Yup, done a LOT of sprinklers in the last 36 years. Gettn a good handle on em. Just don't like handlin the shovel so much.

 

[Rob-D]

Yea probably could, just not nearly as exciting to think about.:thumbsup:

Oldstuf
Yup, done a LOT of sprinklers in the last 36 years. Gettn a good handle on em. Just don't like handlin the shovel so much.

That's true, all those gears turning and a carbide wheel spinning does make me salivate!