Big Stump, Little Tractor

[montero1dfw]

I watched this video on youtube the other day and it amazed me with the ease that this guy was able to pull a fairly large stump out of the ground .


Big Stump, Little Tractor - YouTube


mike

 

[ns_in_tex]

We heard him say 35 to one. Don't know if that was total or just one leg, later he mentioned 7 to one. Regardless, I guess if it was total, then that would be equal to hooking up 35 of those little tractors to that stump.

Reminds me of my childhood days when dad would move chicken houses on skids with one old horse. I guess you just figure how to do the job at hand.

 

[bcp]

If his tractor has 1000 lbs drawbar pull, the 35:1 mechanical advantage raises that to 35,000 lbs pull, minus friction losses in the pulleys.

That's a lot of pull.

Bruce

 

[Tractorrr]

That's pretty cool. A way to get a stump out without a backhoe.

Just looks like you really have to have it set up right and know what your doing. Got to have an anchor tree. Not sure how the anchor tree doesn't get pulled out too. Looks like this way could be pretty dangerous too if not set up right.

 

[N2DFire]

He's Running a 7:1 MA (Mechanical Advantage) system (anchored to the tree behind the trailer) using that to pull a 5:1 MA (anchored to the tree in front of the trailer). That splits the resulting anchor force between the two trees.

Setting them up in this fashion makes them multiply resulting in the 35:1 total MA. Piggy backing systems like this can result in some pretty high MA systems with a relatively low hardware investment (imagine how large & how many sheaves it would take to build a 35:1 non-compounded system)


And yes with forces like those involved, things can get pretty hairy in the blink of an eye.
The up side is that the systems move super super slow - for a 35:1 system he actually has to move the tractor 35 feet to move the stump 1 foot (although the stump gives well before moving a full foot)

The down side is that rope/cordage based systems will stretch and store a ton of energy that will let go in a hurry when things give.
Here's an example from the same guy.
Flying Stump - YouTube

and here's the story behind the magic.
Flying Stump, the Backstory - YouTube


I have watched several of this guys videos before and I promise he's forgotten more about rigging that I'll ever be able to learn so I'll just add

PLEASE - DO NOT TRY THIS AT HOME. :thumbsup:

 

[dickfoster]

I watched this video on youtube the other day and it amazed me with the ease that this guy was able to pull a fairly large stump out of the ground .


Big Stump, Little Tractor - YouTube


mike

I went out to price some block and tackle gear after I saw that. It's not easy to find and boy is it pricey when you do find some heavy duty stuff that would take that kind of strain.

 

[N2DFire]

...and boy is it pricey when you do find some heavy duty stuff that would take that kind of strain.

That's one of the reasons why on Heavy Wreckers the very first storage cabinet behind the cab (which is the largest / deepest one) where that kind of gear is most often stored is referred to as "The Money Box"

The other reason is because if the job requires pulling out stuff in that box, it's going to cost someone a lot of money. LOL

 

[dickfoster]

That's one of the reasons why on Heavy Wreckers the very first storage cabinet behind the cab (which is the largest / deepest one) where that kind of gear is most often stored is referred to as "The Money Box"

The other reason is because if the job requires pulling out stuff in that box, it's going to cost someone a lot of money. LOL

I believe it. Even a single sheave used block will set you back some bucks and a single sheave only gets you a two to one advantage. Even used multi sheaves go for thousands and you'd need two of em so I gave up on that idea.

 

[TheMan419]

That was a neat video. I can see a LOT of ways that could go sideways if you don't know what you are doing. I certainly don't. I'd feel comfortable maybe using a single and getting a 2:1 advantage. Certainly not that set up. But it teaches us if you know the laws of physics anything is possible.