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Block and Tackle Recommendations

Started by flyingparks, May 28, 2020, 09:38:27 AM

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flyingparks

I have a small frame and a treehouse that I want raise with block and tackle. I have started reading The Rigger's Apprentice...a fine read, and it has lit a little fire. Upon searching the internet, all I can fine is what looks to be cheap metal setups that claim a two ton rating. I simply don't trust them, nor do I like to buy cheap tools. I wonder if anyone here can point me in the direction of a quality setup. I'm actually surprised at the lack of options that I uncovered on the internet. Any direction is greatly appreciated. 

sawguy21

You are very wise staying away from the cheap offshore stuff. The money saved won't do you any good when it fails. Have a look at Crosby, that is what we used in the helicopter industry.
old age and treachery will always overcome youth and enthusiasm

Magicman

Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

flyingparks

Those Crosbys look nice! Thank you. And thanks for the knotledge MM.  ;)

Jim_Rogers

One of the first thing you need to figure is the load you want to lift. After understanding that, you can then figure what size blocks you'll need. for example how many shivs you need in each block for the number of lift.
 

  
What that means for example, with my block and tackle I have two shivs in each block so when we pull the line with 100 lbs of force we can lift 400 lbs of load.
After we know the number of shivs and block sizes you can figure the size of the line needed. And check that line's weigh rating.
Here is a picture of my block's label:


 

Another fact about lifting the load is that load going to be completely off the ground into mid air. For example when standing up a bent upon a deck the feet of the post are usually never lifted off the deck. Therefore 2/3's of the load are still on the deck. If a bent weighs 1200 lbs then 800 lbs of it will be on the feet of the post and you'll only be lifting 400 lbs.
So you may have many factors to consider when designing or figuring out what size equipment you'll need.
Good luck with your research.
Jim Rogers
PS maybe someone else will offer you some more advice.
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

Don P

I'll just add, don't forget that pulling at an angle rather than a vertical pluck can add a multiplier to the load. It is the same as the ratios of the sides of the triangle so for instance if you have a 10' tall bent to tip up and a 10' tall pole guyed at the foot of the bent it forms a 45° angle. The rope tension will be 1.414 times the bent weight, the ratio of the hypotenuse to the legs. If the post is only 5' tall the rope pull is 2.2x the load. As the bent tips up the vertical and horizontal reactions change putting more on the legs and less on the rope. The tree tipping calc in the toolbox gets into some of that.


Al_Smith

I suppose it just depends on the weight and length of lift plus the point of attachment .As an alternative you might try flea bay for a chainfall with a 20 foot fall chain .They pop up every so often relatively cheap .
As for blocks I personally would stay away from hardwood blocks and go with all steel with large sheeves .The larger the sheeves the less strain it puts on the line .Those little itty bitty pulleys they use for sail boats should  be just used for that purpose IMO .

flyingparks

Thanks guys. I'm familiar with the block and tackle physics. A while back I read Jim Rodgers thorough post about it. Very informative, thanks Jim. And Don P, I thought I was aware of what a snatch block can do but your explanation of it furthered my knowledge greatly. Once I find a good setup I'll post the raising. It's not pressing, so I'll wait till I find a good setup. Ebay looks promising. As always, I am so grateful for the insight offered on this website. 

classicadirondack

The U S Army rigging manual is available on line as a download.

Dirigoboy

I read an article many years ago about a guy who was building a cabin for himself in the wilderness.  It wasn't Dick Proenneke, but another guy with a similar skill set.  I think his cabin was bigger than Proenneke's, certainly taller, and his main problem, other than doing it all alone, was that as the walls went up it became increasingly more difficult to get the logs up on to the wall.

His solution was a tree in close proximity to the cabin.  He felled the tree, but left the stump around three feet high as memory recalls.  Next, he pared down the sides of the stump until the only thing left was a sizeable tenon in the middle of the stump.  Then he measured up a couple of feet and through-bored at an angle into the butt of the log until he had a hole matching the diameter of the tenon on the stump.  He then dropped the butt of the tree down on to the tenon and built a large wooden box on to the very end and filled it with rock to act as a counter balance.  Mounting his block and tackle on to the tip of the tree he now had a crude crane that allowed him to both pivot AND lift pretty much anything up on to his cabin.
I've always remembered it because I thought it was pretty ingenuous, and I kick myself because I never bookmarked it.  Not sure if that's remotely what you're looking for, but perhaps useful to file away

flyingparks

That's very interesting. I'm looking to rig up something I can take to different sites. I'm working on it. I'm excited to share once I have time. 

Al_Smith

Any rigging for building erection ,tree work or moving a heavy load is just a practical application of HS physics .You can find a zillion examples on the internet .--Google do it .----

flyingparks

Thanks Al Smith. As I stated, I understand the physics involved. I'm really just trying to get input on brands. Lot of cheap stuff out there.

Tom King

Not exactly on topic, but one thing that I wouldn't want to be without is the Maasdam rope puller.  I think I bought it to start with for tensioning non-climb fencing, but it's been used for many things other than that since I've had it.  I loaded a 24" bandsaw in the back of the truck with it, by myself, and it was really no big deal, by nosing the truck up to a light pole, and tying the puller to the pole.

The 8:1 Harken mainsheet system off the Hobie 21 is rated for 3900 + pounds (looked it up after ity-bitty comment).  You don't want to buy one to just use as a block and tackle, but I don't mind using it when I need it.  The cam cleat is a handy thing too.  It might not be rated as high as the tree work blocks, that I think are rated for 10,000 pounds, but it sure does roll easier, and it's already around anyway.

jander3

I like McMasters Carr for equipment.  The Army field manual 125 is a great reference 

 

 

 

Red Earth

Flyingparks were you able to put together a rig for lifting heavy loads?  I am presently working on a similar project.
Thanks

flyingparks

Red Earth, I ended up finding an old set, unbranded, at a garage sale. I tested it out and it seemed to hold fine. I tried to find out what they are but I cant find anything that looks similar.

everythingwood

Quote from: Red Earth on June 30, 2021, 04:56:08 AM
Flyingparks were you able to put together a rig for lifting heavy loads?  I am presently working on a similar project.
Thanks
I built this derrick crane for moving large timbers.  The Army Rigging Manual is a great reference.  It works great.  A few weeks back I used it to load a large riding lawn mower on my trailer to take it in for scrap.  It sure beat winching it up the ramp!
 


 

TimFromNB

I had the same problem this spring trying to fing a set. Luckily, my sawyer had one to lend to me to raise my ridge beam and posts. I've since been on the lookout for an old set for myself. I did find a local rigging supplier as well that apparently can get them in, but I was equally suprised how little availability there is for block and tackle sets online.


TimFromNB


Joe Hillmann

I have a bunch of 15,000 snatch blocks.  I double them up side by side on a clevis for top and bottom blocks when I need a block and tackle.

I think they were about $20 each and I use them as snatch blocks all the time in the woods so using them as a block and tackle just made sense rather than buying something more expensive with much less capacity.

If I wanted to use them as block and tackles all the time I would probably replace the central pins that the pulley spins on with a longer one that goes through both blocks at once.


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