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OT - Homemade Crane Failure

snowman

Diamond
Joined
Jul 31, 2004
Location
Southeast Michigan
It's a beautiful day, so I was out pruning the grape vines. Got no clue what I'm doing, saw something shiny and ended up here.

But check these out! None are mine! Just making that clear.... In fact, I just punched "homemade gantry crane" into google. I don't even particularly know why. But what I got is nothing short of morbid comic gold.

Please folks...copy existing designs, don't build it out of junk just because you got it cheap. The number of pictures that come up with someone standing right next to a 5,000 lb load that is lifted 3' in the air really scares the crap out of me!

http://gofastforless.com/tools/crane.htm

Oh...I see, it's the mills fault for weighing 5500 instead of 4000.

Frank's Trailer Works Blog: Shell Off!!!!!

IMPRESSIVE! OSB and dimensional lumber. Really...I just hope he's not lifting in the wind, could get a little interesting.

http://i232.photobucket.com/albums/ee189/ThompsonBoat/Boat Hoist/SwingSet-01.jpg

That guy gets an award for coolest use of a swingset....and I didn't even realize it was a swingset until I copied the link. I thought someone actually spent time making bent uprights for a gantry.

Gantry Crane Portable Aluminium WLL 5kg Easy Assembly EN-795 Capability - YouTube

That is just a great idea. In fact, I'll be copying that method of assembly!

Finally, which one of you built this? Got plans?

small crane for the kids - YouTube
 
What I don't get is how he was obviously so high with the mill, but it failed like that. Must have had an impact load. I like his comment about the lifting strap causing the failure by pinching off the beam. If your lifting strap is capable of pinching off your beam to a yielding level of deformation, you might have a problem!
 
I did some shopping, and I had to drive about 1000 miles round trip, but I picked up 3 Vestil 1-ton cranes, 16' wide, for $200 each.
 
The Darwin Award hanging in the balance IMHO goes to the guy with the curved glulam supports. Good job on gluing them up but what keeps that trap from just folding left or right? It looks like a 1x2 tacked across the back and friction of the two support bolts is the answer---for now. Wow! That is bad.

Denis
 
The Darwin Award hanging in the balance IMHO goes to the guy with the curved glulam supports. Good job on gluing them up but what keeps that trap from just folding left or right? It looks like a 1x2 tacked across the back and friction of the two support bolts is the answer---for now. Wow! That is bad.

Denis

But to fully answer your question, duh, his workshop...err...storage unit.

I've thought about working in a storage unit, but it doesn't have heat, power or...well, either of those things.
 
This photo is funny to me mostly because of the women folk peering into the sun probably think "ol lord, what has Duanne done now ?" But also being the most worthless per pound milling machine on the planet adds a certain je ne sais quoi to the spectacle :)

crane03.jpg
 
This photo is funny to me mostly because of the women folk peering into the sun probably think "ol lord, what has Duanne done now ?" But also being the most worthless per pound milling machine on the planet adds a certain je ne sais quoi to the spectacle :)

crane03.jpg
Odd that the builder went to all the work to transform bog standard teardrop shelving into a crane.

He could have simply erected a 10' span of said teardrop shelving, made a simple span beam (about 4' sq. looking much
like a pallet with trolley wheels attached at the corners)
to allow trolley to run along shelve cross beams, and had a sturdy, capable crane.

And the footprint would still be the same.....
 
It amazes me the work some people go thru to try to kill them selves. There is a reason why some people spend a boat load of hours learning about load distribution, bending moments, area moment of inertia and all that other stuff that back yard wonders laugh at. Laugh on bro, Darwin is waiting.
 
There are ANSI standards for lifting devices, cranes, etc. People ignore them at their own peril. If you can't do the calculations to prove compliance, don't build it.
 
Actually the kids you-tube crane at the end is pretty damn awesome, would come in good for a whole bunch of things.

IMHO you can design cranes as long as you want crunching as many numbers as you wish, till its proved its self safe with a load test (a suitable factor over planned lifts) its like any other experimental device IMHO it may or may not function as intended. Worth adding more than a few large - very heavy industrial pics using mobile gantry type lifting setups have failed not through themselves, but the surface there on not being able to stand the loadings. Safe equipment alone is no guarentie!

As to the caravan body lift, theoes body’s weigh nothing just big and awkward + easily damaged, hence lifting it with the simple braced structures he made i see no issue in, sheeted timber is a pretty strong and stable thing, equally timer unlike metal normally creaks like fuck before failing, most metal sections are fine till there not and its a milisecound long process, wood will complain and bow like buggery in comparison.
 
To me the issue with the kids crane is that if he is anything like I was at his age he will be testing it to its' limit and beyond ,can I pick dads car up with it ? I would have loved that though and probably much safer than the stuff I used to try and make myself.
 
My wife tells me I'm easily entertained....

I went to an Amish auction once on a very dreary day. There was an Amish-built,but very well made crane mounted on a metal bed with steel wheels, made to be moved about with draft horses. It had ballast weight in the back and would easily have handled a couple tons. It was not part of the auction, but had been used to pick up and place some of the heavier items for the sale.
Now for the entertainment. I stood under the edge of a roof and watched a non-Amish kid of about 12 play with this crane for about an hour in a steady rain. It had a seat and foot pedals attached to a worm and gear to swing the boom left and right and heavy worm gear winches to raise/lower the boom and the load. Hand pedals were used to operate these two functions. Put me in mind of an artillery gunner. Anyway the kid had a ball playing with it, and I had just as much fun watching him!
 








 
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