Constructive criticism

  1. Richard.

    Richard. Member

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    Yes. As said above it would be worth while having tested and it clearly marked up what it’s limit is.
    I could be wrong 8ob but I think when they test them it’s load plus 20%
     
  2. KimB

    KimB Member

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    Problem is. With cranes and what he does, doesn’t take much for it to jump. Swing or create any movement which may damage the beam. Lifting static is fine but if you’re 24m away with the jib and something happens I’d like the peice of mind that it can’t break at all.

    We will. My friend sorts all his certs out in house. We’re going to be designing a lifting cell for testing this and some of the other stuff I’m going to be making.
    As above. We will probably double the weight of it and then lower it down to 1500kg and bounce it a bit with a his hiab. Putting 2t on a 1t beam is fine but if it’s got 1t in it and it bounces badly, the stress may far exceed 5t on the beam.
    Testing is his department though.
     
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  3. arther dailey Member

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    I saw them test overhead gantry crane,low loader in ,pallet cages full of weights, the crane really strained it was good to watch, but well over twice its capacity at that time.it passed..
     
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  4. HughF

    HughF Member

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    If you are planning on doing more of this sort of this Kim, I would strongly suggest you look at obtaining either a more powerful mig or a decent stick inverter. Building lifting stuff with solid wire mig, it can and is regularly done, but personally i’d Like the piece of mind that comes with 7018 or dual shield.the only time I’ve ever felt really happy running solid wire on thick stuff is up around 28-30v with a high argon blend so it sprays nicely.
     
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  5. Brad93

    Brad93 M J B Engineering

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    Dual Shield flux core doesn't always penetrate as well as you think, nor MMA. MIG gives the deepest penetration with spray.
     
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  6. HughF

    HughF Member

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    I’ll definitely agree with that Brad, but MMA could have less room for lof issue on what could be a marginal machine (i’m Late to the party and don’t know what sealey she has) If she can’t get it spraying then I’d say MMA is probably a safer bet, provided she has the experience of this process. If she had a big 3phase machine then spraying would be no issue.
     
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  7. KimB

    KimB Member

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    Hi Hugh, yes my I’ll be buying an AC DC tig which obviously does MMA. at some point I am planning to buy a larger mig too but it’ll do for now.
     
  8. wyn

    wyn Member

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    When i'm sticking brackets and things onto box section i always try and brace it so the forces are acting down the sides of the box section.
    When the bracket is on the face of the box section it can flex the surface and start to crack.
     
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  9. Richard.

    Richard. Member

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    Exactly wyn. Design is certainly your friend if power is lacking. A good design can take the forces and stresses right off a welded joint. In theory you could build that to take a ton easy with a 150 Clarke (I don’t recommend you try) if the design allows loading to be placed on the steel rather than the welds.
     
    daedalusminos likes this.
  10. daedalusminos Member

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    So many people go for the brute force approach, if well designed, this could probably be safely constructed with half the weight of steel
     
  11. Revs1972

    Revs1972 Forum Supporter

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    yeah, but its for lifting.....give me brute force over value engineering every time :D
     
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  12. KimB

    KimB Member

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    I do completely agree. I’d much rather do it like that also. But, I can’t see any way without very expensive tooling to make that work in this application.
     
  13. wyn

    wyn Member

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    You could use two of the plates with the holes and four of the smaller gussets with a pin through the holes to fix a shackle or the lifting hook.

    This sort of thing.


    Photo0019.jpg
     
  14. KimB

    KimB Member

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    Yes I guess so actually. Putting shackles through will just be a pain though.
    I personally don’t see a massive issue with how I’ve done it. At the end of the day it will need the ticket renewing every six month or a year (whatever it is, i can’t remember)
     
  15. arther dailey Member

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    I think Brunel had the same idea,build it strong build it once only...slightly ott perhaps
     
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  16. knighty Forum Supporter

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    if you want it to be stronger... on the next one can you make the eye in the center a bit taller ?

    then you can add a flat bar from just below the eye out to each corner lifting point


    so then instead of your lift depending on not bending the box section, instead it's pulling on the flat bar (which you'll never stretch) and compressing your box section (which you'll never compress... (as long as you don't bend it))
     
  17. Paul.

    Paul. Moderator Staff Member

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    And neither do I,
    I've made loads of this kind of thing over the last 40 odd years and probably wouldn't do anything much different for a 1 ton lift, as long as its properly load tested and examined it will be fine,
    I'd bet that in a destructive test the material would fail before the weld gives way, but it'll take more than a ton to cause that to happen.
     
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  18. KimB

    KimB Member

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    Exactly although. There’s doing it where it’ll work and how everyone else does them and there’s making twice the work for yourself.
     
  19. KimB

    KimB Member

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    Again, I’m my eyes just needless work. Each corner is only holding no more than 200-300kg. That weight spread over 480mm leverage, it doesn’t even flex with that IBC. My friend put a straight edge to it.
    Oh off course. Something that’s quite easy to overlook is the fact that each corner wouldn’t be exceeding 250-300kg as I’ve just said above. That over 480mm long 5mm box, it didn’t move at all.
     
  20. Richard.

    Richard. Member

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    I agree the design is more than capable of supporting a ton of weight but I cannot see 10mm thick material failing before 200 amp solid wire mig welds will in a DT. I’d confidently say The welds would go first.
     
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