Homemade Post Hole Digger

[cnicholls]

Ok, here is an interesting build...

The story is this, someone (not me) converted a 4.11 rear end differential into a post hole digger using what i believe to be a 24" auger from a manure spreader.

The one side was cut and welded solid, and the input shaft was sleeved for a pto shaft. I bought it as is from craigslist for $200

I converted it to hydraulic using a combine feeder motor and two #50 chain sprockets also from a combine.
It worked great after i added two teeth to the bottom of the auger. Digging a 24 hole 44 deep, the entire head goes down into the hole.

UNTIL.... I live in northern Ohio in clay country.. I was digging posts for a pole barn and hit a rocks, feeling cocky i decided to "work them out" i ended up bending the auger, so.... i heated up the blade, bent it back and welded some 3/8" plate to it... then dug 4 more holes and the axel shaft broke... ****! not knowing what year or make the rear end was, I abandoned the rear end and bought a new gear box made for an auger... and that痴 another post to come.... And by the way the new unit has a chain guard

Chad
Chad's Home Improvement, Furniture and RV Projects

 

[Iplayfarmer]

24" is a large hole. What are you putting in these 2 foot holes?

It sounds like whatever your setup is, you're going to need a better shear pin design. You need a fuseable link in the system somewhere to keep you from breaking and bending stuff.

 

[cnicholls]

Digging footers for pole barn in ohio you need a min 18" footer 42" deep.

 

[jml755]

As you found out, gearboxes are sized for hp and implement sizes. A 24" post hole auger is BIG. Plus, it wouldn't surprise me that a manure spreader auger is NOT designed to take the loads imposed by ph digging. I think the utility trucks around here typically use 24" augers and I've seen some landscape companies use big augers mounted on skid-steers for planting trees. And all of them have been engineered for the task at hand and size of equipment. Cobbling stuff together "might" work but then again it might "fail".

I agree with iplayfarmer that you need to make sure you have a "fuse" somewhere. Either a pto clutch or shear pin. Make sure you DON'T use a Grade 8 bolt like a worker for a relative did. He was tired of breaking shear bolts on the brush hog. Duh, they were breaking for a reason, saving the drivetrain. Luckily, relative found it after the guy was long gone but before any damage was done to the tractor.