hydraulic posthole digger questions

[davedj1]

I am contemplating building a hydraulic posthole digger, the only one I can find similar is this one; NorthStar Hydraulic Earth Auger — 270cc Honda GX Engine | Auger Powerheads, Bits + Extensions | Northern Tool + Equipment + Acreage>Auger Powerheads, Bits + Extensions&cm_cat=Google&cm_ven=Aggregates

Now they say their pump is a single stage , 6 gal/min
I am thinking of using a 2 stage logsplitter pump, cheaper and I would think if the digging is good, you would want it faster?

Any help is appreciated, I have never dealt with hydraulics so.........
also what motor should I look at?

I am thinking I will build it so that it can attatch to the back of my truck , in the hitch, maybe I will add two more recievers , one on each side of the hitch.

I want power down as well so I will need advice on valving.
thanks,
dave

 

[J_J]

You can use any hyd for the auger flow, but it is preferred to use a single stage for the pump flow as you have the GPM's, and the high pressure.

Whereas with a two stage, the auger will spin fast until it hits the ground and then it will turn real slow with high pressure.

How are you going to turn the two stage? They are usually turning at about 3600 rpm to produce the flow.

 

[davedj1]

Glad you cleared that up for me, I guess a single stage it is.
I am planning on building a powerpack of sorts, maybe get one of those HF 6.5 - 9 hp Honda knock off's and attatch the pump to it.
Maybe I'll get an old jeep or pickup and build a backhoe on the back with removable bucket then I can attatch the phd to it. I deffinately want down pressure.
I've been building several polebarns lately and between hand digging and paying a skidsteer with auger, I figure I can build something that I can use and save/make me money in the long run. Plus I like building this sort of stuff.

 

[J_J]

A 9 HP engine is necessary to turn a pump, pumping 5 GPM's, and a potential pressure of 2500 psi.

 

[davedj1]

J J, you are a wealth of information! Thank you for that. I made the decision today to purchase an old truck, jeep, whatever that has a pto tranny so I can run a pump, I will build the backhoe on the back with a removable bucket and swap the auger in. I may not do this asap but be sure I will look to you for more guidance in the near future. The hunt is on for the right rig. I just saw an old bucket truck in town that is in very nice shape, when I say old I'm talking 70's. there is no tool boxes on the back , just a flat bed, maybe I could use the bucket to set posts and trusses? With the backhoe on the back?
dave

 

[dusty3030]

How about a used skid steer and a trailer to pull it with? $15,000 and a little shopping and you could have a good skid steer, trailer, and all the attachments you are looking for.
If your budget is less you can fix one up for a little less. If you already have a trailer to haul it around with even more so.

I would think you would be money and time ahead in the long run.

 

[davedj1]

no budget for a skidsteer...lol
I enjoy building stuff, it keeps me sane. (or proves I'm insane)

 

[psj12]

I saw some on Ebay. They were listed as high flow and low flow motors. The low flow would allow them to operate from your tractor remotes. They showed one bolted to the side of the FEL bucket. Looked like a good idea as they are easier to watch and if they get hung up they can be reversed.

 

[dusty3030]

2310 Ditch Witch

How about one of these as your base vehicle? Got your hoe, trencher, and power for hydraulics for your phd already figured out. Plus it would be easier to get into tight spots, and you could see where you are going. It will probably be hard to line up a truck or a jeep on a hole, you won't be able to see the tip of your auger to line it up.

 

[dusty3030]

You could rig up a phd on the side of it and some diverter valves from the bh hydraulics to run it. Actually, it would be a neat set up for running holes in a straight line. Line up on a string line with the tires and go straight from hole to hole if the phd was running at a 90deg angle off of one side of it. If you could get it rigged up right you could run some holes in a hurry and never have to get off of it.