[denrep]

For anyone wondering why not just buy a driver, it's not so simple as to just rent or buy a driver for this job. The driver will probably have to push post sizes and lengths outside of the typical commercial driver's specs and reach. Next thing is that three-point hitch mounting is out, so the mount will have to be a custom piece too. And the work is not like fence job out on the open prairie, where many posts can be driven in a long day, to control rental costs. Besides, if we just bought everything, what would we post on WeldingWeb? Politics?

I did turn up a hydraulic vibrator removed from a cable trencher's plow. I haven't played with it yet, not sure if it may be usable for post driving.

I'm sort of convinced that the builders of commercial drivers are hampered by weight limitations.

So with Alfred's motto of: "Don't force it, get a bigger hammer" in mind, tonight Alfred and I performed a quick heavy-hammer feasibility study, to get a feel for how much weight has to drop how fast, and how far, to drive a beam home.

Here's the prototype hammer, 927 lbs, plus four sticks of 7018 :laugh:
View attachment 40762
It's inverted here for welding, during the test run the square block will hang down, as the striker.

We chained the "hammer" to a forklift carriage. The forklift has a restrictor which limits carriage drop speed, so there will be no "Demon Drop" rides today. :laugh:

8' tall beam in compacted sandy soil:
View attachment 40763
The mast was tilted so that the "hammer head" was level.
A few gentle strikes to start the beam, and then a check and adjustment for plumb.

Once the beam was started plumb, I let it have some hard hits; the beam stayed plumb.
Short rapid hits seemed to be more effective than long drops.

I drove the beam into compacted sandy soil seven feet.
The slowdown started at about four feet.
View attachment 40764
Rock solid, and as plumb as would be expected from a student driver.
I may piggyback another 800 lbs on the hammer to see what that does.

Now... Does anyone have an idea for a decent post puller. :laugh:

I plan to digest the study results for a few days as I think over some post driver options.

Thanks again for the suggestions. :waving:

 

[Boostinjdm]

you said you found a vibrator...what happens if you rest that hammer on top of the beam for downward pressure, and then vibrate the beam?

 

[Sandy]

I did turn up a hydraulic vibrator removed from a cable trencher's plow. I haven't played with it yet, not sure if it may be usable for post driving.

Most of those that I was familiar with back in the day were just gear driven off centered weights (think crank shaft with no rods) and an intended Vibration Per Minute of around 700 or so. They were made to break up hard soil or fracture rock in the forward progression via an up-n-down action. Dunno, I like the 'whammo' mentality of the big weight.

Short rapid hits seemed to be more effective than long drops.

I'll guess that, in this case, acceleration is limited by the fork lifts drop limits therefore there was little noticable difference in real impact between longer or shorter drop distances. So in this case nearly as much work done in a short drop as a long drop do to a lack of increased acceleration so the more IPM the quicker the work is done.

Sounds good right now. Later it may change.

 

[Sparky8370]

You should just buy one with all that money laying around everywhere.

 

[the Q]

a capstain winch to run your weight would work. simple frame to guide the weight and post, and a capstain to line up the post and drop the weight.

 

[BlindViper]

what state are you in?
where are these blocks at? I am thinking anvil
http://www.weldingweb.com/attachment.php?attachmentid=40722&d=1256612217

 

[Scott Young]

don't forget to hard face your hammer face.

 

[Tractapac]

Denrep, I'll post some pics of a Kinghitter we have. Good to see that imc188222 has one, too. (Made in NZ - but don't tell farmersamm) Ours is an older model and is innovative in that having a 15 foot mast, you can lie it down to rest the top in a support by the front wheel of the tractor, for road use. Helps keep it clear of power lines etc. Later models have a folding mast where the top section folds down.
The maker's site is: http://www.fairbrotherind.com

6'6" post 8" dia. rammer has been moved out 9" from it's "home" position to align with desired post position. Also the diagonal ram angles the mast in or out at right angles to the tractor.

Cap resting on post top, has a spike to locate it. Vertical ram is the lifting method for the monkey. Three pulley sheaves on the ram and three below. 55 feet of wire rope. Ram is single acting. (and fairly quick too!) Dump to tractor reservoir is via the orange/pink hose.

Right hand plough arm is hydraulic also for positioning. Gives fore and aft movement to mast base. Large central ram is the one that lies the mast down for transport. Ahead of that is another ram that gives fore and aft adjustment at the top of the mast.

Here you can see the transport ram and the fore and aft adjustment ram and also the hydraulic plough arm. You can see the spike under the post cap. Also the post cap has a UHMWPE top to it to prevent metal to metal contact from the 550 pound monkey.

10 posts at 3.6m (12 foot) centres and then an 8m (26 foot) gap to the next set of ten.
Fairly straight row. With the spike in the post cap, you can control the direction of driving reasonably well. Part way down, I disengage it all from the post to check for plumb and then re-engage it and push or pull wherever to correct any drift. None of these deadmen or the strainers that go in above them are pointed and the rows are all quarter rounds and they're nigh impossible to control if you sharpen a point on them.

If you'd like any more info or pics or measurements just ask.

 

[Tractapac]

And now for something completely different!

Here's an adaptation of a Bobcat for post hole boring, post ramming and shelter pole erection. Kiwi ingenuity again.

Note the duals for traction. The set up shown is for post hole boring but it also accepts a retractable rammer to allow it to drive under the kiwifruit canopy (6 foot) and then put the rammer mast up and replace any damaged posts. It can also act as a jib when they're erecting tall shelter cloth windbreaks.

One photo hasn't uploaded, I'll do that shortly.

 

[Tractapac]

Now for the missing photo.

Removing one set of drive wheels and adding the castor at the rear maintains the maneuverability of the Bobcat but doesn't tear up the ground like a skid steer.
It's driven from a seat above the front left wheel.
Another twist in case it helps.

 

[DSW]

Denrep that sure looks like your pup in that pict. Not only do you have money just lying around the shop, you send your dog to Kiwi land to check out possible options!

 

[burnandreturn]

Where I live it is impossible to use a ram device because of the terrain. Banks and ditches and such. A tractor with post hole auger is useless. First you can't get to most of the places I need to build fence. Second the ground is to rocky. The auger gets stuck. I tried a 15,000 dollar hydraulic auger on my excavator. It would only dig about fifty percent of the holes and be stuck by a rock. So I had a special chisel made for my hydraulic hammer for my excavator. The chisel is four feet long! I can now put a hole anywhere in 10 seconds. I also have a 8 inch square flat foot for the hammer. I can drive most posts in with the flat foot. The excavator goes where I need. I just drive along the side of the line and swing over to put a post in. There is some skill needed to get the posts straight but after maybe 50 posts I got real good at having them plum and inline. And if one is not just right I can just yank it out and try again. The long chisel was expensive to have made but worth every penny. I only use it on my own property or my friends. It is a two man job though to do it right.

 

[denrep]

Sorry I haven't been back, thanks for the replies and pictures. Lots of good ideas.

Where do I start?
First things first, let's get the money thing cleared up :laugh:
The problem with "all that money" lying all around, is that it all carries the same serial number!

The dog - Pac's dog sure does look like kin. I sent a pup to Honduras once, maybe he kept right on going. :laugh: The black muzzled mongrels are sure a fine breed.

The blocks - Sorry BlindViper, can't get off the blocks for your anvil project. The blocks are a premium around here. Check with Oldiron2 and his "free" thread, in his area bigger pieces than that fall out of the sky! :laugh:

No real progress since the test.
I've been thinking about different options, mostly a "monkey" on an H-beam.
I was hoping to go all hydraulic, and direct acting, no cables, ropes, chains.


Thanks again

 

[jackh]

personally id stick to the old school way of driving them by hand. much more precise than letting the hydraulics go at it. ive heard of them getting off a bit and being driven in too far to correct when doing it with the machine. doing it by hand is much more precise but a pain in the ***

 

[MrLeadMan]

Maybe 6" beams or 8" pipe to be sunk about 4' in average soil conditions, nothing too rocky or solid.

jackh I've driven zillions of those steel t-posts over the years with a maul or driver but uhhh....I ain't about to attempt no six inch H beam or eight inch pipe old school by hand.

 

[G3farms]

When Dad bought our farm he was putting in new line fence. Cedar post that were sharpened on the end and driven in the ground with a 16 pound sledge. He would stand on the back of a trailer to get high enough to drive it in the ground. There was a young fella helping him (not me I was just a few years old) and kept wanting to drive a post in the ground and Dad would always tell him no because he was too little. Well Dad finaly gave in one day, little fella grabbed the sledge, reared it back over his head to drive it home in on lick, missed the top of the post...............sledge swung down and went under the trailer with little fella still holding tight to the handle, it jerked him off of the trailer and head first under it. Needless to say he did not want anymore of the post driving.

I guess he learned something at the "old school" lol

G3

 

[imc188222]

Did I catch a hint, from another post, that you have finished the post driver and are using it? Can't wait to see pics of it if that is the case.

 

[denrep]

This'll be kind of disappointing, but I bought a production model hydraulic post driver and attached it to a rough terrain fork lift, but it just doesn't have the "punch" for the big posts, although it works fine for smaller ones.

Then I built a couple of simple drop hammers... lift, release, and KABOOM! The post gains a few inches. But after about a dozen big posts the job was snowed out. I'll dig up some pictures.

I would like to build the "guided missile" a large "monkey" weight riding an H-beam carrier. I'm still stuck on the hoist mechanism design. I'm sort of leaning towards a hydraulic motor for hoist, and a clutch that could release the weight for a true free drop.

Good Luck

 

[Brad Blazer]

I'm pretty sure the Shavers use a long single acting hydraulic cylinder and a very free-flowing exhaust. The cylinder diameter is pretty small - you want to maximize speed and minimize exhaust flow. A 1" cylinder will lift about a ton in a straight lift. Check out the Shaver HD12. They talk about driving unsharpened RR ties. Might be a good size to copy.
http://www.shavermfg.com/DrSp.html
http://www.shavermfg.com/movie.html

 

[burnandreturn]

Why couldn't you build a diesel piston type of pile driver? If you really want a hammer type of driver it might be your simplest solution.