How strong is steel

[Sodo]

Elastic beam deflection calculator

Online calculators are useful if you can understand the load diagrams. Goof around with them until you can find how many inches (tenths?) deflection of a wood beam that you know to be strong enough. Then with the steel sizes available, use the beam calculator to get the same deflection.

 

[RedNeckRacin]

They have a handbook for steel. Its about 2.5" thick sitting on my shelf at home. If you really want to get into theory and all the multiple failure modes, there are college doctorates that will dazzle you. For backyard tools, scoping out the already made implement will be your best source of info. If you have a welder and a way to cut it don't worry about breaking it! You can already fix it. If your not sure if something is strong enough. Do what we engineering types do, multiply by 2 for a factor of safety!

 

[CobyRupert]

Geez,
Spend the money for an hour or two of a structural engineers time.
Have your ducks in a row when you visit (span dimensions, loading, size of steel you're considering, etc..). It won't take them any time to give you some answers or look up the info in the RIGHT table.
Now, if you want them to draft plans, details and put a stamp on it, that is what takes time and costs money.

..but a ("back of the napkin") 1 or 2 hour consult should be abut $75-$200. Well worth it.

 

[Sodo]

Do what we engineering types do, multiply by 2 for a factor of safety!

If you just double the steel, you don't need no stinkin' engineer. Copying an existing (engineered ) design then doubling it probably results in a factor of ten.

Geez, Spend the money for an hour or two of a structural engineers time.

I don't think this is feasible for a small project. Looking for other examples of similar loading and construction is more feasible. Of course you have to be able to assess 'similar loading and construction'.

A lot of engineering is to obtain necessary strength and safety factor with minimum materials (cost or weight). There are varied goals, including pointing of the finger. There is very little to gain employing an engineer for a small, one-off project (unless he's free). Free engineering is often possible because they are often socially challenged, in fact will continue to give away free engineering long after you have tired of it.

I suspect this is nothing new to the OP, who seems confident that he can make good enough decisions with an equivalent to span tables. If you weld with metal, but build structure like wood, the resulting structure can be far stronger just due to the fixation of the steel joints (and many other reasons too).

 

[RedNeckRacin]

If you just double the steel, you don't need no stinkin' engineer. Copying an existing (engineered ) design then doubling it probably results in a factor of ten.


....

Awe come on. If you think you have just enough strength and double it, it doesn't hurt anything as long as it serves the purpose. As far as today's implement go, be careful about that factor of ten business. Have you seen the scrap that tractor supply sells? I think you would need to multiply by 10 sometimes to get a decent piece of equipment!

 

[Sodo]

Sorry, was thinking of overhead eqpt which likely has a factor of 5. Other stuff certainly is less. Doubling of a known sufficient strength, is a good way to do it.

Basically an engineer can't calculate any safety factor unless he knows the loads. If you don't know the loads, engineer can't help you unless he is allowed to "assume" the loads, and if he's smart, will be very very conservative. And your item will be very very heavy

I think we're swatting flies with a hammer.

I think OP just needs some steel form equivalents of 2X8s ( & etc)

 

[RedNeckRacin]

You mean its overkill to swat flies with a hammer? Awe man!


(Although, shooting groundhogs with a 30-06 is a lot more fun than using a .22!)

 

[Groo]

Quick lesson;

The cross sectional moment of inertial is basically the number you want to look at.
Ixx
Structural A36 Steel Channel Section Properties Table Chart -* Engineers Edge
example:
C5x9 (C channel 5" tall and 9 lbs per foot) is quite a bit weaker than C6x8.2 even thought he C5x9 is heavier.

 

[LD1]

Quick lesson;

The cross sectional moment of inertial is basically the number you want to look at.
Ixx
Structural A36 Steel Channel Section Properties Table Chart -* Engineers Edge
example:
C5x9 (C channel 5" tall and 9 lbs per foot) is quite a bit weaker than C6x8.2 even thought he C5x9 is heavier.

Yep. Height (depth) gains more capacity than heft. Dont matter weather its channel, i-beam, tubing, or wood studs.

Use the same calculations for wood to find the Ixx. Then use that to calculate deflection and loading of a beam. The Ixx for a piece of wood that is 2" x 4" is gonna be the same as steel. The difference in stresses and deflection come down to the strength of material. If all you are comparing is various shapes and sizes of steel, simply looking at the Ixx and Iyy numbers is a good indication as to what will be stronger.