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Too_Many_Tools
03-16-2006, 12:36 AM
I am kicking around the idea of building a gantry crane with an aluminum I-beam.

Last week I found a source of surplus aluminum 6061-T6 beams (10' long by 8" high by 5" wide).

With the plan of using one for a gantry crane, what would the lifting capacity be for a 10' beam with adequate safety factors included?

I am hoping to make this a one man assembly effort so I am looking for ideas for an adjustable height supports.

Here are some approaches...

http://www.wallacecranes.com/ratchet.htm

http://www.spanco.com/pages/gantryaalum.php

Any other suggestions for buiiding an aluminum gantry crane?

Thanks

TMT

webowser
03-16-2006, 04:43 PM
You need to know more about the beam to determine its load carrying capacity such as flange thickness, web thickness, exact depth and flange width. This information will allow you to determine the structural properties of the beam such as section modulus and radius of gyration which are necessary for structural calculations. Its capacity also depends on the design of the frame and how it is supported. It is assumed that you are certain of the type and temper of the aluminum beam in question. If you are uncertain of that, then materail testing would be required to determine the modulus of elasticity, the yield strength, and the ultimate strength. Without a lot more information your question can not be answered.

Bill

Too_Many_Tools
08-03-2006, 01:05 AM
I am kicking around the idea of building a gantry crane with an aluminum I-beam.

Last week I found a source of surplus aluminum 6061-T6 beams (10' long by 8" high by 5" wide).

With the plan of using one for a gantry crane, what would the lifting capacity be for a 10' beam with adequate safety factors included?

I am hoping to make this a one man assembly effort so I am looking for ideas for an adjustable height supports.

Here are some approaches...

http://www.wallacecranes.com/ratchet.htm

http://www.spanco.com/pages/gantryaalum.php

Any other suggestions for buiiding an aluminum gantry crane?

Thanks

TMT


Me again....

I am still kicking around the idea of building a gantry crane with an
aluminum I-beam.

I found a source of surplus aluminum 6061-T6 beams


Both beams have the following specs....


The flange width = 5", the flange height = 8", the web thickness =
1/4", the flange thickness = 3/8"


One of the beams is 10' long while the other beam is 9' long.


What kind of loading will these beams take?


With the plan of using one for a gantry crane, what would the lifting
capacity be for a 10' beam with adequate safety factors included?


I am hoping to make this a one man assembly effort so I am looking for
ideas for an adjustable height supports.


Here are some approaches...


http://www.wallacecranes.com/ratchet.htm


http://www.spanco.com/pages/gantryaalum.php


Any other suggestions for buiiding an aluminum gantry crane?


I also plan on using a STEEL beam clamp on these ALUMINUM beams...any
problem with that?


Finally could someone point me to a discussion of how to calculate
proper loading on a gantry crane that a layman can understand?....I
wish to learn to do this properly.


Thanks


TMT

Forrest Addy
08-03-2006, 03:39 AM
Consider some form of lateral bracing before you settle on the safe loading for your I beam. Look carefully ar Wallace gantrys for inspiration and construction details. There's lots to learn from a successful design.

Roughing in numbers from a table for a 10 ft span using the aluminum beam data you provided and a safe working load of 15 Kpsi I get about 10,000 lb for a distributed load at abut 5/8" deflection in the center. A point load like a lifting trolley would halve the safe working load.

You cannot take rely on these numbers. They're first approximations only but I'm guessing your gantry could be rated for 2 to 3 tons, no more.

Rustybolt
08-03-2006, 09:10 AM
Machinerys hadbook can give you formulas for figuing bending and shear. Personally I'd be hesitant to use alum as the cross beam. Some alum alloys, while they might perform like steel on tensile tests, let go in a rather spectacular manner. If it were me i'd stick with the known abilities of steel. Besides isn't it going to rather expensive?

tonydacrow
08-03-2006, 11:45 AM
I'm just curious why you want to use aluminum rather than steel. Is weight the big factor? Obviously, a steel beam would be much stronger, cost less and take up the same a mount of space. Also, IIRC, aluminum is much more likely to fail catastrophically…

Scishopguy
08-04-2006, 12:32 AM
TMT

While working in the shop at FSU we built an overhead crane out of two aluminum I-beams. They were from a Military surplus jet engine dolly and were about the size you describe. We had a budget one ton hoist and steel trolly that fit the I-beam perfectly. We mainly used the hoist to lift vises, chucks, and big rotary tables on and off the machines. The beams were hung from brackets bolted to the concrete ceiling with lead calking anchors. The ceiling was a coffered type and the cast web of the coffers was 8" thick with one inch rebar in it. It was suspended from the steel u shaped brackets by some 1" threaded rod. These brackets were on 4' spacing and the I-beams were attached end to end, forming a track about 18' long. We had the machines oriented in such a way that the hoist traveled across the tables and beds of the most used equipment (2 bridgeports and 2 lathes). The heaviest thing we ever picked up was a 10" Sheldon Lathe and cabinet which I guessed to weigh 1000lbs. It worked flawlessly and did not even creak or groan.

Jim (KB4IVH)

Too_Many_Tools
08-04-2006, 10:39 AM
I'm just curious why you want to use aluminum rather than steel. Is weight the big factor? Obviously, a steel beam would be much stronger, cost less and take up the same a mount of space. Also, IIRC, aluminum is much more likely to fail catastrophically…


Thanks for all the responses...they are appreciated.

The reason why I am considering an aluminum I beam is that I am trying to build a gantry crane that ONE person can assemble on site to lift the various machines I purchase. An aluminum I beam would be one that a person could lift into place...a steel one would not be. The lifting capacity of the crane will hopefully be in the 1-2 ton range.

I do understand the concern about aluminum failing suddenly. I also agree that people almost always overload lifting devices.

Here are a couple of sites that discuss portable cranes....your opinions?

http://www.hospitalrigging.com/

http://www.easilymovedequipment.com/

Finally, if one wants to build a lightweight gantry crane that would lift a couple of tons, how would you do it?

TMT

WJHartson
08-04-2006, 10:45 AM
When Kaiser aluminum built their rolling mill in Ravenswood, WV they used aluminum for almost everything. The admin building had aluminum door and frames, wired with aluminum, ceiling tiles, stairs, railings covers over columns and others. In the plant some of the air lines were aluminum and some of the overhead cranes were made of aluminum. The largest aluminum crane was 200 ton main block with a 50 ton aux. It serviced the roll shop and the main motor bay in the plant.

Joe

bob101
08-04-2006, 11:02 PM
I'm in the structural steel business and the problem I would forsee with aluminum and I have seen in the past is bolt pull thru. Not sure how you would hang your beam but if bolted bolt thru on aluminum can be a problem.

Personally you can buy pretty small structural steel beams and be good to go. Even better buy what they call a "S" beam that's made exactly for that and you can get trolley hangers etc... for that purpose that fit on a "S" beam. Barring getting an "S" beam just get a regular "W" (Wide flange beam - what most people refer to as an I beam which they really don't make). Rent a lift/forklift/offer free beer to friends to put it up then.

If you have to buy straight from a wharehouse - call em and ask what they sell the most of like say a W6x15 (6inches deep and weighs 15 pounds per foot) so you can get a good deal or drops etc....Don't look up the exact load you need and get the next bigger beam that can carry it and insist on that size - go up above it whatever to get a common beam size. There are some oddball beam sizes on the load charts that are almost impossible to get or they roll like every 3 months etc...Best bet find a small couple guy fab shop and tell them exactly what you want and let them order it for you and you go pick it up. I buy several hundred tons of steel a week and I know the dealers we buy from normally don't want to mess with someone buying 2 - 20ft. beams cut to lenght and you pay 100X more per pound that way - literally.

Info on steel beams can be found online by searching thru an AISC manual.

Leigh
08-05-2006, 11:12 AM
McMaster-Carr Supply http://www.mcmaster.com has an assortment of I-beam clamps on the lower 2/3 of page 1393 of their catalog. Type the page number into the search box at the upper left.