Advice on welding 10t lifting eye

[olek]

This is being overthought and over engineered, that lug on the OP is massively over engineered for a ten ton lifting eye. There are lifting lugs on some heavy plant that we move about that have a fraction of the strength/material for a similar lift. I always think of the words of a sage fabricator I worked with yonks ago that would "engineer" this type of thing using his experience without drawings or calculations, he would remind me of the strength of a small bolt and in this case one half inch grade 8 on a straight lift would come close to ten ton. http://www.rdfasteners.com/pdf/boltstrength.pdf

Bob

Your table, it gives shear strength of the bolt in its long dimension, or also if cut with an effort against its diameter?
Too bad those imperial measurements do not speak to me that much

 

[Gwil]

Re over engineering, a friend said to me once that if I built Formula 1 cars they would never break.....but they would never, ever, win!

 

[Cobbler]

Re over engineering, a friend said to me once that if I built Formula 1 cars they would never break.....but they would never, ever, win!

Someone involved in racing told me once "if it's not knackered when it crosses the line it's been over engineered"

 

[olek]

That is funny I am not certain yet of the shackle dimension to be used but the program tells yet that the bolts touch the weld so the bottom plate may enlarge or the upper one ,qde less thick (I did not enter the width only the lenght of the vertical plate, I suppose à few rules apply from one dimension to obtain the other)

Weld size for 10 T minimum 0,22" (with 70xx LH) 24 inches area of weld (perimeter ?)

I am amazed by the weld resistance

If I am not wrong, the allowable bearing stress is 32,4 kips, so 1,5 the 10T expected. Is it a lot oversized ? may be not so much, but the ones with experience seem to say otherwise, so I shut up

Looking qt an excel table of the Crosby shackles, it is the most used brand?

PS 10T-force = 22 Kips in the converters

 

[olek]

Here is what I came with based on a 12t force

. file linked

indeed the thickness of plate is about half of what is shown

used a shackle for chains 25 ton limit (min x2 load factor)

Noticed that on the document provided by Brad there is a bevel both sides at the base of the lug , not in the computed design

Depending of the orientation of the pulling force, the weld side varies from 1 to twice if not more

That was fun, anyway, I feel as a marine engineer

 

[BigDan83]

Wow, not been on here for a couple of days, and there's all these replys.

Thank you all so much for your help. Unfortunately I was unable to get any more info on these, and had to refuse to do them. They have now been sent back. Shame because I would of liked to do them, but just didn't want to take a risk. If they can't even get a detailed drawing of what they want, what chance do I have doing them.

Thanks again

Dan

 

[Bonser]

Hi you should use 7018 low hydrogen rods, it will deffinately need U/Ting, heres ours and this thing only wieghs 60 tons. We build and install oil rigs so a lot of 2000 ton lifts. All welds will undergo U/T inspection