Post driver

[Mee]

Local agri dealer sells them and the hammers wear out, they use cylinders with a thick base (30mm) plate and fill with concrete and cap with a thinner plate.

If I could make a suggestion, fit wear strips on moving parts as they are easier to replace than a full strip down.

 

[anto44]

A good source of big rounds is a decent hydraulics shop. You would find that kind of diameter in their scrap bin.

Bob

+1 for this. Place local to me reconditions hydraulic rams. They regularly scrap trailer tipping rams that kind of size.

 

[addjunkie]

Plenty old siezed post knockers about. Cheap enough to buy and harvest or repair.

 

[500e]

Don't feel bad Spark Plug cut it off this bit
Just making the safety clamps for the QH + the transport clamps for the weight the ratchet strap was just to stand the thing up to see if it hung OK
Have done over 600 piles with it now min depth 10 Mtrs

 

[Spark plug]

View attachment 108992 Don't feel bad Spark Plug cut it off this bit
Just making the safety clamps for the QH + the transport clamps for the weight the ratchet strap was just to stand the thing up to see if it hung OK
Have done over 600 piles with it now min depth 10 Mtrs

Yeah it's some post knocker that.

 

[brewdexta]

I saw a video of one of those in action and couldn't quite figure it out, so I take it the springs help to pull it back down faster?

Yes I believe so, I haven't used it for a while but now the field is firming up sufficiently to get the neighbour's tractor in I have about 80m of fencing to do so will be giving it a go soon.

 

[Rig Pig]

So are you going to put the weight on a trip so it releases from the ram for the drop or go super size on the hydraulics?

 

[gav0994]

So are you going to put the weight on a trip so it releases from the ram for the drop or go super size on the hydraulics?

most agricultural post knocker work by a single acting hydraulic ram pulling a rope that the weight is attached to up a mast. Once at the top of the mast, you then release the hydraulic pressure in the ram allowing the weight to slide back down the mast at speed. To achieve a quick drop the hydraulic hoses need to be at least 1/2" and ideally 3/4" to allow the oil to flow out the ram quickly back to the tractor oil tank. The top of the ranges machines are made by Bryce Suma; Protech and Vector Powerdrive. There is plenty of good videos of them in action on YouTube.

 

[Spark plug]

So are you going to put the weight on a trip so it releases from the ram for the drop or go super size on the hydraulics?

I think the key will be to use the smallest possible ram that is capable of lifting the weight, so it will refurn faster than the weight can fall.

 

[Mee]

You have another option, some have a hydraulic ram to lift the weight and at a set point it activates a cam and releases the weight to freefall, and at the bottom of the rams stroke it picks it up again.

 

[wyn]

On a rope type Parmiter knocker i used to use, the geometry of the ram and arm meant you could release the ram before the weight got to the top...............The momentum of the weight would carry itself up the last 1/4 of the mast. Once you got the hang of it this meant a much smoother operation without the ram pulling the weight and smashing in to the top of the mast.

 

[gav0994]

You have another option, some have a hydraulic ram to lift the weight and at a set point it activates a cam and releases the weight to freefall, and at the bottom of the rams stroke it picks it up again.

this is the best style of knocker I'd say. plenty of options on movement. No complicated cams on rams etc. just a ram raising the mast with a pulley system moving the rope. release the oil and the weight pulls the mast down as it falls.

 

[Kent]

I'm in the beginning stages of planning / building a tractor mounted post driver. I'm starting to collect materials and the likes.

I have just got a couple of universal beams one of witch will be used for the main upright, I have some hydraulic rams that may or may not be of use for this project. But the main thing that has been giveing me a headache is the hammer weight that will hit the post.

There are two options that I have in mind either a big lump of square or round steel bar, the other Bering a fabricated container made from steel then filled with lead. Both have there potential problems as the target weight I'm aiming for is 200kg.

Dose any one have any suggestions for the best way to do this, or any better ideas?

Been using one just today actually. The rams do the work. The hammer is just an 18" square 3/4" plate with sturdy gussets to what seems like some super chunky shs

 

[Spark plug]

You have another option, some have a hydraulic ram to lift the weight and at a set point it activates a cam and releases the weight to freefall, and at the bottom of the rams stroke it picks it up again.

The only drawback with this idea is you can't control the force of the hit, so if on soft ground it will be difficult to control the post depth, if your just aiming for another inch or so.

 

[Screwdriver]

Wouldn't a molten lead fill quickly become loose? I made up some super heavy flypress balls by filling hollow spheres with lead. One of them has worked loose and rattles...

PS I'd probably go for an electromagnet release. You can pick and choose the drop height from the cab.

 

[gav0994]

Wouldn't a molten lead fill quickly become loose? I made up some super heavy flypress balls by filling hollow spheres with lead. One of them has worked loose and rattles...

PS I'd probably go for an electromagnet release. You can pick and choose the drop height from the cab.

working from inside the cab is not ideal. constant jumping in and out to work the post driver. The standard method of a hydraulic ram pulling a rope connected to the hammer weight to slide it up and down the mast is the most simple method.

 

[awemawson]

Most of the demonstration videos show nice even pre-shaped posts

... it's a whole different ball game with split chestnut spiles that vary in cross section and straightness

 

[Rig Pig]

most agricultural post knocker work by a single acting hydraulic ram pulling a rope that the weight is attached to up a mast. Once at the top of the mast, you then release the hydraulic pressure in the ram allowing the weight to slide back down the mast at speed. To achieve a quick drop the hydraulic hoses need to be at least 1/2" and ideally 3/4" to allow the oil to flow out the ram quickly back to the tractor oil tank. The top of the ranges machines are made by Bryce Suma; Protech and Vector Powerdrive. There is plenty of good videos of them in action on YouTube.

Ah I see, the pile drivers I worked on were rather larger, the diesels had the ram rased by a crane until it hit the trip point, releasing the ram from the carrier letting it drop and hopefully start. The hydraulics were a bit more involved with a nitrogen precharged cap to double the affective weight of the ram.

 

[Screwdriver]

working from inside the cab is not ideal. constant jumping in and out to work the post driver. The standard method of a hydraulic ram pulling a rope connected to the hammer weight to slide it up and down the mast is the most simple method.

Sure but if it's electromagnetic release, I could do it from here

 

[addjunkie]

working from inside the cab is not ideal. constant jumping in and out to work the post driver. The standard method of a hydraulic ram pulling a rope connected to the hammer weight to slide it up and down the mast is the most simple method.

Fencing is a two man job if your trying to do it quickly. One drives the other post knocks. That knocker in the video looks very good, i like the steel plate that sits on top pf the post, saves damaging the top of the post which many, espescially the more simple ones do.

But the one on an arm the articulates for me are best, so many times you just cant get in with a tractor. And more often than not where you cant get the tractor in ground is toughest to hand fit posts.

Or fit the basic one to a digger arm.