My new spreader beam plan (visited steel yard)

This is a continuation of my effort to make a suitable spreader beam
for lifting engines and pallets.
I visited a steel yard in Chicago this morning and picked up some
scrap. (I am NOT proud of what I paid for other stuff besides scrap).
Anyway, for $20, I picked the following:
1) One 4"x3.5'x3/16" steel plate
2) Two 1.25"x1.25"x3 ft square tubing pieces 3/16" wall (heavy wall)
My plan is to weld them longitudinally, so that, when seen from the
side, they will look like this:
o|o
`
that is, the square tubing pieces will be welded to both sides of the
plate forming "ribs".
That would make a 3" or so structure that, I hope, will be rigid
enough not to buckle under loads of up to 1,000-1,500 lbs. I would
drill holes in steel plate for hooks and such.
Most of the weight will be carried by the 3/16" plate, with the ribs
serving mostly to prevent buckling.
As for welding, I will just use 6013 stick electrodes. Will paint it
with some "farm equipment green" oil paint.
i
Reply to
Ignoramus20979
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Igor, that sounds plenty strong. The beam itself won't fail, now watch how you design your load points and you should be OK. You don't need to do 100% welds; 25% skip welds (3" out of a foot) should be enough for the stiffeners. If the steel is rusty, 6011 or 6010 would be a slightly better choice of rod. The paint will last 3X as long with a good coat of red primer under it.
GWE
Reply to
Grant Erwin
That $20 was most of the cost of the HF leveler unit that requires no fabrication and provides the adjustable balance function.
Pete C.
Reply to
Pete C.
Yes, I think that I do not need continuous welds, though I think that it will look better and will be easier to paint with continuous welds.
The steel is NOT rusty.
OK... I have some greya primer, I think, but I could get red primer.
Thanks..
i
Reply to
Ignoramus20979
Yes,... But... This one is going to be quite a bit longer, good for lifting pallets... Though I do not claim to be a big authority on these things...
i
Reply to
Ignoramus20979
Realize that unlike shipping containers, pallets aren't really designed to be lifted by the corners. The pallet jack or forklift normally supports the load from below. When a less than perfect pallet splits in half and drops the load during a lift you'll know what I mean.
Pete C.
Reply to
Pete C.
You will be better served to separate the tubes to the top and bottom of the plate, like such:
[]| []| | or | |[] []|
No, it doesn't meet our natural inclination to make things symmetrical, but it will carry far more load than with the tubes at the center of the plate... Better would be 4 tubes, but I'm working from your materials list...
denny - old plant engineer
Reply to
Denny
Denny, I kind of agree that it would possibly provide more strength, but would't you say that even the original design would have strength far in excess of 1,000-1,500 lbs that I specified.
thanks
i
Reply to
Ignoramus20979
lbs is not "strength" it is a unit for weight.
Nick
Reply to
Nick Mueller
Better ASCII art
| []|[] |
Reply to
Ignoramus20979
It's marginal, at best. At 1500 pounds the max bending stress will be about 21000 psi, which is at the limit for common structural steel in braced construction, and I'm not accounting for the holes in the plate. You've got an unbraced, slender beam.
Will your beam fail? It probably depends on how the load behaves while it's in the air. Is it safe for lifting 1500#? I'd say no.
Ned Simmons
Reply to
Ned Simmons
Hm, Ned, how did you calculate it? It is interesting.
i
Reply to
Ignoramus20979
Plain old statics and strength of materials. Machinery's Handbook has the Cliff Notes version if you want to check my work, though it may not have numbers for allowable stresses or data on buckling of beams without lateral support.
Ned Simmons
Reply to
Ned Simmons
Ned, I am lost, but there is lateral support? The cross section would look like this
| []|[] |
the [] symbol depict a 1.25" square tubing with 3/16" wall.
i
Reply to
Ignoramus20979
Iggy,
Some time ago, we put in a new septic tank. The people who manufactured and delivered the tank, unloaded it with a spreader bar that had chains that hugged the round tank, which weighed about 2,000 lbs.
Based on what they used, I built one myself, out of some rectangular tubing. Although I don't remember the dimensions exactly, it was something like 2"x4"x0.25".
When we lowered the tank into the excavated hole, it worked like a champ. It flexed, but did not fail. We used it several times to lift the tank during leveling operations.
There is tremendous strength in mild steel.
Vernon
Ignoramus20979 wrote:
Reply to
Vernon

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