C-Clamp Issues

[jmac]

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.

[soundman]

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.

[cdub260]

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.

[gafftapegreenia]

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.

[mrb]

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.

[jmac]

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?

[themuzicman]

a side arm won't do the trick?

[derekleffew]

Originally Posted by jmac

...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?

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

[gafftaper]

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:

Grade 7

[derekleffew]

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?