# Jib crane question



## jpfabricator (Jul 9, 2013)

Im going to build a jib crane in the shop Im constructing. I was wondering how to find the information that will tell me how big my "I" beam should be to support a 200# load @ 12' from the pivot end. Can anyone help me out?


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## Codered741 (Jul 9, 2013)

That's a complicated question with many factors involved.  There is no chart that will tell you exactly which size, there are simply too many variables involved.  There is a book of formulas, the Steel Construction Manual, published by the AISC, which will give you the formulas, but provides little help in solving them.  But I would be happy to help!

First, a couple of questions.  

1.  Are you planning on putting in a support line/arm?  
2.  If so, is that arm under or over the bar?  
3.  What kind of hoist are you planning on putting on the crane? (Eg. Electric, chain fall, rope and pulleys)

A 12 foot unsupported cantilever, meaning without a support, will require some beefy material, but the load that you are looking for is fairly low.  

Once I get a couple of answers, I will be able to tell you exactly what size beam you will need.  Though off the top of my head, you will be looking at at least a 4-6" standard flange beam.  And without a support line, you will need a pivot that is VERY beefy.  

-Cody


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## Tony Wells (Jul 9, 2013)

Excellent points CR brings up. There are many variables. I would suggest mimicking an existing design if possible. And even then, perhaps fudging on the heavy side. I've engineered and built a couple of free standing, 360° jibs, with 6,000 lb cap, and there is quite a bit to it, from the bottom of the concrete anchor, to the stops out on the tip of the beam.

Here is some good reference material to pore over. You can build your own, but beware of liability when building your own design for someone else. That's another game entirely.

https://www.gorbel.com/resources/products/jibcranes/Documents/JIBTEXT.PDF


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## TOOLMASTER (Jul 9, 2013)

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## Tony Wells (Jul 9, 2013)

I used wide flange pattern in the beams I have built. Otherwise, you have to go way overboard on the size to gain the rigidity you need. I have seen H-beam used in jib beams also, but the standard trolley design is made for the tapered flanges on standard I beam. Of course, if the is a fab-from-scratch, the trolleys may be shop built as well.


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## Codered741 (Jul 9, 2013)

Here are the two pages from the SCM which contain the formulas for determining beam size for the two different types of beam designs that i described.  Let me know how you want to design it, and ill run some numbers for you!

-Cody


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## sniggler (Jul 9, 2013)

If you didn't see it look at the Dave's post in the recent "how do you lift big stuff" thread, nice simple setup. When you need a long reach you have to really beef things up if you are going to do any heavy lifting.

You need a safety factor engineered into the system and if you're not sure you need an "engineered system".

Just as an example:

OSHA fall protection standards require, "Lanyards and vertical lifelines which tie-off one employee shall have a minimum breaking strength of 5,000 pounds",


We used to use 1/4 wire rope slings choked to beams for fall protection anchor points (a place to tie off your harness lanyard) No good as the choked capacity is .48 of a ton. With all the factors safe working load vs. breaking strength is problematic. Enter engineered systems for fall protect with the manufacturers testing and certifying, a yo-yo type retractable can use 1/4 wire rope.

Bob


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## Ray C (Jul 9, 2013)

Please see this... Maybe it helps because, it gives some materials information for different span lengths.  You must visit the web site to see the specific data but here's a nice view of the overall design.

http://www.lkgoodwin.com/more_info/...fs300_baseplate_mounted_jib_crane_1_ton.shtml


Ray


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## jpfabricator (Jul 9, 2013)

Let me start with this "I have opperated winch trucks, and heavy equipment for over ten years. I have been trained in heavy lifting and rigging. I have a very healthy respect for gravity, and enough common sense to know if it dosent look safe, ITS NOT!" 

Here is my cartoon animated drawing (CAD)


The black upright is a piece of 4" .275" wall pipe
The purple base is a pice of .250" steel triangle 24"x24"x24"
The image on the right is an overhead view
The green lines represent 2" pipe outriggers, the 2 side pieces will be bolted to the concret, and the rear piece will extend through the wall and be cemented into the ground
The orange top support will be some 3/8" cable I have on hand
I have 2 dozen .500" wedge ancors for bolting this all down.
Total height will be 10', and 9' to the top of the jib arm.

My moto is "Id rather have over kill, than be killed"
This jib will use a 1/2 ton chain fall, and I will build my own trolly to keep overhead clearance to a maximum. My trolly stop will be a 3" pipe socket that a temporary support leg can be placed into for added piece of mind.
The jib will be centered behind the lathe, and the end will rest over the mill. Its main purpose will be to install and remove accesories, and also be to lift materials the back dosent need to lift.


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## stevecmo (Jul 9, 2013)

As Tony alluded to, and Ray's picture shows, one of the easiest thing to overlook on a jib crane is the base and anchoring system.  It's easy to focus on the beam and pivot connection and overlook the base.  The calculations get pretty complicated and are dependent on the thickness (and quality) of the floor slab.

Be careful.

Steve


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## Ray C (Jul 9, 2013)

For some reason, I cannot see the picture now but, the link works and shows very good images and information.

Ray



stevecmo said:


> As Tony alluded to, and Ray's picture shows, one of the easiest thing to overlook on a jib crane is the base and anchoring system. It's easy to focus on the beam and pivot connection and overlook the base. The calculations get pretty complicated and are dependent on the thickness (and quality) of the floor slab.
> 
> Be careful.
> 
> Steve


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## sniggler (Jul 9, 2013)

Concur typical garage floor slab will not have rebar= break floor pour reinforced pier use j-bolts to anchor. top stay of jib has very acute angle, back stays are making a lot of space useless and could have a more acute angle, gusset base plate gusset jib boom at column, gusset from above to below pivot point. 

Consider rigging trolley beams next to lathe 2 perpendicular 1 parallel parallel beam to trolley inside the flanges of perpendicular beams for increased head space.

Bob


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## Rbeckett (Jul 9, 2013)

The formula for figuring the thickness of the jib arm is in the Machineries Handbook.  I always refer to it if I am looking for a numeric solution because that is what that book excels at the best.  I don't remember exactly where it is, but there have been discussions about this on other sites and the answer was found in the book.  I too tend to over engineer my projects to insure complete safety when I use that kind of equipment.  Coming from a rigging and wrecker back ground has given me a really healthy respect of that kind of work and the stresses involved.  If a cable snaps or a block fails some one is going to get hurt, it never fails.  So I plan for it and prevent the failure by exceeding the requirement every time.  HTH.

Bob


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## psween (Jul 11, 2013)

When my dad built a new shop a few years ago he had me engineer a crane that was anchored to and built into one corner of the building itself.  The corner vertical beam was a very beefy angle, with diagonal braces down to bolts in the slab, which was engineered to handle it.  The main beam is a 10" deep I with 6" flanges, I believe 3/8" thick (would have to check).  The bottom line is, Machinery's Handbook has easy to use formula for calculating a cantilever beam, which I used.  Also double checked with some other beam formulas I was familiar with from engineering school, and it all told the same story.  For reference, that 10" deep I beam was sized to handle a 700# engine out at it's full 10' extent, so it's a lot more load than you are talking. Just remember to apply a generous safety factor (I used 5 times the expected load).

Patrick


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## Dave Smith (Jul 11, 2013)

is there some reason you are wanting a jib crane and have you ruled out a portable aluminum gantry crane? for just the 200# at the end of a jib crane a lightweight adjustable gantry crane could handle that weight with ease, but would be able to lift a half ton also. we used portable adjustable gantry cranes at work and they were very handy. maybe you need a jib crane, but they are very expensive to put in a shop, compared to gantry cranes.  just a thought    Dave--:thinking:


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## jpfabricator (Jul 11, 2013)

I looked at a couple of gantry style cranes, I feel I might be going that route as the gantry will accomidate all 3 machines, and the door. Thank yall for all your help. Now if anybody has a few gantry designes I would love to see them!:whistle:


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## Rbeckett (Jul 11, 2013)

I agree that a gantry set up would be more flexible and capable of reaching more places in the shop.  It is also capable of moving the load once you have it slung.  just lower it as close to the floor as possible and move right along.  we moved big ole detriot diesels in Iraq for Hemmts and tank haulers.  The cab was a mere 23 tones and once we lifted it off we could access the engine and trans as a unit.  we changed those engines very frequently due to oil leaks and supercharger run aways.  Once it runs away the Army wants it replaced without question.  So we replaced a lot of perfectly fine engines because of "Policy" what a waste of funding and resources.  Oh well I just turned the wrenches I did not dictate policy or decide what was done to the vehicle.   I just hated to see such a waste.   Just the oils and chenicals were more than I would have imagined due to the cost of getting it into theatre.  One gallon of 15-40 oil was valued at 35 dollars and a 1 liter bottle of water was billed at 3 dollars a bottle.  Just my .02 worth though....

Bob


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