Thread: Post Drivr Ideas Needed

The simple old ones I saw was just the hammer running up and down inside two channel iron beams with a wire rope connected to a pulley that was driven by the tractor PTO...

You should see the OHS requirements for new ones today...

Random thought

to knock in star pickets I use a 2" diameter pipe with a piece of solid 2.5" diameter steel bar welded on top, and a couple of handles welded on the side from 1/2" rod. The pipe slips over the post and yours truly lifts the driver, letting weight (maybe a bit of extra push) created the hammer.

Can this be scaled up?
The tube would mean the thing is self guiding and less risk of squashing something.
Still many problems--

Some form of lift would be needed (power or lever??)
Some form of quick drop???????

Still need a post hole!

sigh

Originally Posted by .RC.

The simple old ones I saw was just the hammer running up and down inside two channel iron beams with a wire rope connected to a pulley that was driven by the tractor PTO...

You should see the OHS requirements for new ones today...

Maybe something along these lines but with a link chain with a drive sprocket at the bottom and idler at top, perhaps one mounted each side of the channel. The chain has hooks which lift the weight (hammer) and as the hooks follow the chain around the radius of the top idler sprocket the hooks release the weight and the hammer falls.

Originally Posted by HavinaGo

Random thought

to knock in star pickets I use a 2" diameter pipe with a piece of solid 2.5" diameter steel bar welded on top, and a couple of handles welded on the side from 1/2" rod. The pipe slips over the post and yours truly lifts the driver, letting weight (maybe a bit of extra push) created the hammer.

Can this be scaled up?
The tube would mean the thing is self guiding and less risk of squashing something.
Still many problems--

Some form of lift would be needed (power or lever??)
Some form of quick drop???????

Still need a post hole!

sigh

I have a star picket driver very similar to this I made myself. The weight is the important part. Mine is welded inside the tube.

We have used a device like this in the past to drive posts. I have a heavy steel box built of 8mm angle (or so) 500mm high about 250mm square. Heavy steel base and filled it with lots of long heavy steel rods etc. I then welded grader blade edging on to the outside. This was lifted up by a foot operated lever mounted to a winch boom (homemade) on the back of a ute. A cable ran from the lever up to a pulley on the boom then down to the weight. Two people operated it. Myself and SWMBO. We drove in some strainer posts with it but had to first bore a hole by hand that was just slightly small than the post. One of these posts is now lifting out of the ground.

This device sort of worked but after SWMBO got a clip on the head by the edge of this huge lump of steel we decided that:
1. It was too dangerous
2. We were getting too old

With a normal post driver such as mentioned by .RC. I have driven 10 inch posts 4ft 6in in the ground with a 4inch diam by 3ft deep pilot hole. They do not move. These use a hammer weight of about 200 to 250kg.

These designs use a slip clutch driven off the tractor PTO to turn a winch drum which lifts the hammer up and down the mast. The clutch is operated at the rear of the tractor by the operator who also does all the adjustments etc for guiding the post in straight.

There is also a hydraulic type which I believe uses high speed rams which are beyond my price and ability.

The latest versions use vibration such as is found on a plate compactor etc. I have not been able to find out any details on the precice methods used however. A simple rotating offset weight would be the simplest construction of all these types but I don't know if that type of vibration will work and what sort of variables I am looking at.

.RC. I work in a winery. Vineyards surround us on all sides. Vineyards would be one of the biggest markets for post driving. Now they are even using plastic posts. We have had a serious chest injury from a broken post and the death of a young contractor from heart failure during post driving activities in our vineyards. I know about the OHS issues. This can be a good thing however as due to the first mentioned injury the company no longer allows the use of second hand posts so they are all sold. If I load myself I can get posts suitable for intermediate use for nothing.

Dean

Weren't there old school pile drivers that were powered by a mix of kero and diesel? sort of like an internal combustion motor without the conrod and crankshaft. You stood off in the distance with a string to a valve you pulled to stop it working. It'd pay to find a diagram of one rather than reinvent it and have a potential accident along the lines of "Anvil Shooting" on your hands.

Hi Dean,
Years ago a farmer asked me to copy a post driver he borrowed so I took some pics. They might give you some ideas.

Phil

and one more, sorry about the quality.

Phil

Phil.

That looks like the same model I was using. Thanks for the pics as I now have a visual idea instead of memory to go by.

The guy I was hiring it off has not spoken to me direct since I last collected it from him when it was returned to have the top bearings repaired. He kept ringing SWMBO while I was at work and giving her instructions about it. The cable frayed and he replaced it with an unsuitable stiff cable. He kept ringing SWMBO. I finally left a message on his answering machine (you could never catch him on the phone) to not talk to my wife and to talk to me. The next day he picked the unit up while SWMBO was in the shower and have not seen him or the unit since. He also hasn't asked for any hire fees. My reason for saying this was purely due to common sense. I was operating the unit and I am the mechanically minded person. Better to get info direct rather than second hand.

Anyway I am not about to go and ask him if I can have a look at it.

The unit you took pics of appears to be missing a post support carriage or maybe this is the basic model which does not have it. I notice a chain and hook low down on the mast which would hold the post in position. There is another carriage which slides on the mast like the hammer. This is used to clamp the post using a chain and hook. Pic number 2 shows the hook but this one has had another hook welded on to it. The hook I am talking about is the slot in the steel plate right above the welded on hook.

The chain shows in pic 6. I am used to seeing these mounted on a sliding carriage. The chain is attached with a fairly strong over centre locking lever so you clamp the post up near the top when you start. This controls the post so when adjustments are made sideways by the mechanism in pic 10 the post was physically moved by the driver. The mechanism in pic 10 was welded up on the unit I had. Same with backwards / forwards tilting which is acheived thru the 3 point linkage adjustments.

Dean

Originally Posted by Graziano

Weren't there old school pile drivers that were powered by a mix of kero and diesel? sort of like an internal combustion motor without the conrod and crankshaft. You stood off in the distance with a string to a valve you pulled to stop it working. It'd pay to find a diagram of one rather than reinvent it and have a potential accident along the lines of "Anvil Shooting" on your hands.

This is a new idea to me. I have never heard of these. Sounds dangerous. Unfortunately standing off in the distance does not enable you to control the angle of the posts. Even with the control given by the unit I was using I have some posts with a lean.

One other thing I should mention is that I am now intending to bore a hole just prior to driving a post, using a double water jet on the end of a bit of pipe connected to a fire pump. This bores a hole and lubricates the hole. Wet soil packs tighter than dry. The traditional method to make the jets is to bash the end of the pipe with a hammer until you only have two small holes left, one on each side.

Dean

google diesel pile driver or hammer, though I'm not sure how easy it would be to home brew.

"Wet soil packs tighter than dry" Are you sure about this? I've seen post driven into wet soil that could be lifted out once the soil dried. Though maybe its just that type of soil.

Stuart

Originally Posted by Stustoys

google diesel pile driver or hammer, though I'm not sure how easy it would be to home brew.

"Wet soil packs tighter than dry" Are you sure about this? I've seen post driven into wet soil that could be lifted out once the soil dried. Though maybe its just that type of soil.

Stuart

My understanding based on soil types to build a shed on, is that clay content is a big factor, i.e. high clay soils shrink a lot when drying whereas sandy soils do not shrink at all when drying. I think clay is known as a reactive soil.

Oldneweng: Diesel pile drivers have been around for roughly a hundred years or so and are a proven technology. Out of interest I had a look on the Internet for a diagram of one and they seem remarkably simple in design, though I expect the devil will be in the details such as materials used to make one. You'd still need some sort of guide rails so whether it's simpler to make than a dropping weight post driver would be a moot point.

Originally Posted by Stustoys

google diesel pile driver or hammer, though I'm not sure how easy it would be to home brew.

"Wet soil packs tighter than dry" Are you sure about this? I've seen post driven into wet soil that could be lifted out once the soil dried. Though maybe its just that type of soil.

Stuart

You just proved my point. However Graziano has hit the nail right on the head. When I say it packs better, the particles slide easier because of lube from water. Clay soils and sandy soils are very different. Lets just say that I have sandy soil and a 10inch post driven 4ft 6in deep down a 4inch by 3ft deep wet hole is not going to move for a long time without a large external force. In sandy soil the area surrounding the post will be tightly compressed by the driving force.

Arround here the oldtimers drive their posts during the wetter months as they go in easier, straighter and stay in better. Some soil types may not be suited to this method. I have heard stories of fencing over sand dunes where in the lower sections you need to dig a big hole, sit the post in and fix cross bars on the bottom of the post before filling back in. This stops wire tension from lifting the post out of the ground.

Graziano

My understanding based on soil types to build a shed on, is that clay content is a big factor, i.e. high clay soils shrink a lot when drying whereas sandy soils do not shrink at all when drying. I think clay is known as a reactive soil.

Sounds right to me

Oldneweng: Diesel pile drivers have been around for roughly a hundred years or so and are a proven technology. Out of interest I had a look on the Internet for a diagram of one and they seem remarkably simple in design, though I expect the devil will be in the details such as materials used to make one. You'd still need some sort of guide rails so whether it's simpler to make than a dropping weight post driver would be a moot point.

I will look into them. Thanks for the ideas.

Dean

Having had a look at the diesel pile driver now I think that it may be a bit more complicated than I want to undertake at this time. It would also need some form of winch to lift it up onto a post. That means the cable drive system is half way there.

It is an interesting subject however. I wonder what the OHS requirements are for them.

Dean