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C-Clamp Issues

Discussion in 'Lighting and Electrics' started by jmac, Feb 9, 2009.

  1. jmac

    jmac Active Member

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    Quick questions:

    Trying to hang fresnels where we have no pipe.. Will a C-clamp safely secure to a run of unistrut which looks to be about 1" +/- thick?

    Also, what is best way to obtain a 12" or so extension between C-clamp and fixture yoke, to drop fresnel below some ductwork?

    Thanks.
     
    mark and (deleted member) like this.
  2. soundman

    soundman Well-Known Member

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    This might border on a rigging issue but I would do what any AV company would do. Take off the C clamp and get yourself some threaded rod. Get a few channel nuts for the unistrut and tread the rod into that and then attach a light to the other end. Done deal.
     
  3. cdub260

    cdub260 CBMod CB Mods

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    A trip to a Home Depot or Lowes will solve this problem for you. In the electrical department, near the conduit, you'll find channel nuts designed to fit inside Unistrut. They come in packs of 5 and both Home Depot and Lowes cary them in 1/4 in. to 1/2 in bolt sizes. If your Unistrut is 13/16" size, you will need to remove the spring from 1/2 in. channel nuts in order for them to fit. It's possible that you may need to go down a size to 3/8 in. channel nuts. I would also recommend that you pick up some fender washers to place between the yoke and the Unistrut, or you may have trouble pivoting the yoke.

    That should do the job.
     
  4. gafftapegreenia

    gafftapegreenia CBMod CB Mods

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    I would have to say both responses are pretty much the way it's done.

    Regardless of what you do, MAKE SURE IT HAS A SAFETY CABLE.
     
  5. mrb

    mrb Active Member

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    if youre dropping it down with threaded rod, make sure you use the thick square nuts that are made for unistrut, fender washers cave into the unistrut when you tighten a nut into them.

    another trick to make it look better is to slide an appropriate length of 1/2" or 3/4" (depending on threaded rod dia) over the threaded rod. Make sure you still have double sets of nuts at each end, the sleeve is purely cosmetic, dont tighten the light up against it.
     
  6. jmac

    jmac Active Member

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    Thank you all for the lesson in u-strut hardware.

    Any standard method for adding an extension between yoke and C-clamp, when clamping to a pipe?? BMI Vertical Extension Tubes, $30-$40...? Anything cheaper?
     
  7. themuzicman

    themuzicman Well-Known Member

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    a side arm won't do the trick?
     
  8. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    1/2" threaded rod. Jam nut at the top against the stud of the clamp; nut, yoke, Nyloc (or two nuts) at the bottom.
     
  9. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    A message from the Safety Nazi:
    Since we are overhead lifting here I always use quality bolts: Grade 5, Grade 7, or Grade 8
    Especially since I live in earth quake country. Yeah it'll add a couple bucks to your project no big deal.
    Don't just buy the cheap Chinese ones in the bin at Home Depot. Get the good ones. With the marks on the heads like this:

    [​IMG] Grade 7 [​IMG]
     
    Last edited: Feb 10, 2009
  10. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    1. I don't recall ever seeing grading on Unistrut hardware.
    2. Do you know of a source for Grade 5 or Grade 8 1/2"-13 threaded rod?
    3. How do you tell what grade the nuts are?
     
  11. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    :naughty: Fastener quality when overhead lifting is VERY important.
    I purchased some of the official gold Unistrut brand bolts and I believe the markings were actually grade 5.1 or 5.2 There's nothing wrong with using standard Unistrut or "Super Strut" brand bolts. What I was meaning is don't go buy your bolts from the bin of Chinese crap at Home Depot. Buy good ones.

    My bad, I was talking about the original question, not the threaded rod.

    I know you are an old dog... care to learn a new trick? Check out the bottom half of this chart for standard ASTM markings on nuts.

    Okay! I admit I wasn't thinking about that when I posted, all I was really trying to say is don't use the cheap bulk bolts for overhead lifting. But it's fun to be right!:mrgreen:
     
  12. SteveB

    SteveB Well-Known Member

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    For whatever reason, the HD channel steel is slightly wider and I mean slightly, then Kindorf, with the result that HD channel nuts will not work on Kindorf (which is generally gold colored). So you end up going back to the electrical supplier for Kindorf nuts.

    SB
     
  13. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    [user]gafftaper[/user], I couldn't agree more: "Fastener quality when overhead lifting is VERY important." "But we're only going to be lifting her a little ways off the ground.":evil:

    You should know better than to try to teach me anything.:mrgreen:

    Interesting that your chart seems to indicate there's no such thing as a Grade 5 or Grade 8 nut. On the truss bolt set-up I keep for training purposes, the bolt is a Grade 8, but on the nut: at one-two o'clock is a |, at three o'clock is a dot, at nine o'clock is a %-looking sign, except triangle\triangle. What grade is that, or are those just manufacturer's marks?

    [user]SteveB[/user], you were the first person I'd ever heard use the term Kindorf. Is it more popular than Unistrut in that foreign land (Brooklyn) in which you live/work?
     

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