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HSM Rigging: Hindsight is 20/20

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  • #61
    Originally posted by adatesman
    Don't care to argue the point with you, but will say that DMM is known for rating their breaking strengths conservatively and any way you cut it, it's stronger than the mystery metal chain and hook that came with the hoist. Plus it gave over 10:1 safety factor on an 800 pound lift, so I'm not exactly following what your problem with it is.
    And what did you pay for that Buck Rogers BS carabiner? You could have had certified shackles for less I'll bet:
    http://www.amazon.com/Crosby-1018375...shackle+crosby

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    • #62
      Less than $15, IIRC. Thing is, I needed them for rigging a certain type of climbing anchor (roped solo), so had them anyway. Had the basement not been a disaster area from making room for the lathe I would have been able to find my stash of proper lifting hooks, but after half an hour of looking I gave up and used the carabiner since it was plenty strong enough at 10:1 safety factor. So really, what's your beef?
      Last edited by adatesman; 06-27-2012, 10:28 AM.

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      • #63
        Was hoping Tdmidget would respond here with an answer to my question, but it seems PM was good enough for him. Please correct me if I'm misreading your PM, but it seems his beef is that I was not only using non-lift-rated equipment, but endorsing that behavior as well.

        Thing is, aside from pointing out that these carabiners were not standard, off the shelf ones you'd find at the hardware store the only thing I said was that they had over a 10:1 safety factor for the lift in question. Not sure how that got taken as an endorsement, but there you go.

        Sorry this got your hackles up, Tdmidget, but frankly I couldn't care less if you do rigging professionally. If you'd like to debate calculating WLL from a 3 or 4 sigma breaking strength rating I'm all ears, but kindly drop the "BS Buck Rogers" attitude first.

        Btw, the sling I used was a piece of 1" tubular webbing tied with a ring bend. And the blue buckle thing out to the end of the bed was from Home Depot. If you want to nitpick my HSM rigging, I'd suggest you start there, as I would be very, VERY surprised if this setup wasn't fairly typical, excluding the carabiners.
        Last edited by adatesman; 06-29-2012, 05:03 PM.

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        • #64
          related - but this was done by "pros", same lift method as green mill

          "how not to move a 100 year old statue:

          http://www.youtube.com/watch?v=cSaSe2s64w0

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          • #65
            Not pro's at all.
            Watch the video, instead of lifting clear he scopes round whilst it's still sat on the base causing the stature to tip and then gravity takes over.

            Totally different to moving a machine that can't snap off in the middle, even after the accident note the base is still held and still level.

            Even if this statue had been rigged differently the operator error of scoping instead of lifting would have caused damage.

            Very easy to sat welded to an armchair offering advise, different if it's on your time and dime.
            Put it like this, if I had to lift this slotter again tomorrow I'd do nothing different.
            In fact it would be hard to lift it differently giving it has no lifting eyes and the top casting isn't central to it's C of G.
            .

            Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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            • #66
              John. Are there slots cast into the base of that slotter for straps?

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              • #67
                Not slots as such but like many machines the corner feet extend down so when it's sat on the floor only the corners are touching.

                That makes it hard for a strap to fly off the edge given the weight.
                There is nothing to stop them working closer together other than the wide strap biting into the metal and the fact thy are not that wide apart anyway.

                Now if this was say a long lathe with a strap either end and centre slung then you would need some method to stop the straps moving in.
                Usually you strap thru some closed fitting on the machine like bed webs.

                Possibly what many don't realise is that there are charts telling you strap angles and how much these derate a lift.
                .

                Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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                • #68
                  Originally posted by Ian B
                  I recently had to lift my Harrison M400 with a Hiab crane. The lathe weighs around 2 tons.

                  I first hung a 5 ton rated ring on the Hiab's hook. From moving the lathe on rollers, I knew where the lengthwise CG was, and I'd marked this with chalk. I used 3 strops, each with an eye at each end.

                  The first, heaviest strop went around the gap in the bed, which was about 2" to the left of the CG. This took most of the load, and was rated at twice the lathe's weight. This strop was wrapped, I adjusted it as the Hiab was taking the load.

                  The second went around the bed, outboard of the tailstock end bed foot. A bit of messing with shackles got the machine to hang horizontally. Not much tension on this one, but enough.

                  The third went around the spindle, behind the chuck. Just took up the slack, again with shackles. There to prevent it doing a quick 180 degree rollover.

                  Lifted it no problems. Time spent on slinging *always* pays off...

                  Ian
                  This is pertty much exactly what I did, Except I think I added an extra strap or two from the lathe to the collumn of the cherry pickery to keep the lathe from spining as I moved it. Also had some other minor straps wherever looked good, One main super heavy duty strap rated like 5x the lathes weight at least and 2 heavy duty straps rated for the weight of the lathe, one near the tailstock and the other around the chuck.
                  Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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                  • #69
                    Possibly what many don't realise is that there are charts telling you strap angles and how much these derate a lift.


                    index screw machines had these little 1/4 circles cast into the machine base.
                    A couple of steel bars and lifting slings in an X and the weight of the machine kept the bars in place.
                    Index had a chart for all of their machines.

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