Conventional Fixtures C-clamp question

[thatactorguy]

Hey all!! I recently bought a few old Altman PAR 64s and ordered 3 Eliminator PAR 64s about the same time. The Eliminators, to my horror (seeing how it's almost Halloween and all) didn't come with C clamps. Our grid is made of 2x4, just over 14' above the deck. We don't have any problem hanging fixtures with REAL C clamps like those found on S4, Altman, etc (they're hung on top of the 2x4), but I am concerned with fastening those cheap looking C clamps on our grid. Has anyone else encountered this? Did they work? If not, what was your solution or workaround?

 

[ship]

Provide a like to the other fixture/clamp & photo of how you are doing it. Choice for me would with safety cable, Unistrut mounted to the lumber.

 

[Amiers]

Yeah pictures.

Never seen a C clamp wrapped around a 2x4.

 

[josh88]

Yeah pictures.

Never seen a C clamp wrapped around a 2x4.

I mean I can see how it could be done, but I wouldn't and don't really want to think about it anymore :shock:

 

[RonHebbard]

I mean I can see how it could be done, but I wouldn't and don't really want to think about it anymore :shock:

@josh88 @Amiers While were journeying down the path of things people do but you wish you hadn't seen:
Some folks hook standard lighting C-clamps over the edge of a horizontal 2 x 4 on edge and tighten the bolt directly against the lumber. If / when they continue to do it in the same location they keep tightening the bolt until it's digging further and further into the wood.
In the next phase they learn they can screw half of a 2" back-flap hinge on to the side of the 2 x 4 for the C-clamp's bolt to bear against and protect the wood.
In the third phase the truly inspired learn they can skip the wood screws and simply insert half of a 2" back-flap hinge in place while clamping the C-clamp and the C-clamp's bolt will hold the half hinge in position until strike time when a 'lesser God' strikes the lamp and wonders what the noise was when gravity flung the non-secured hinge half on the floor or the hard hat of the assistant footing the ladder. The assistant was wearing their hard hat and safety glasses, right??
Toodleoo!
Ron Hebbard

 

[Chase P.]

I second the Unistrut. I hear a lot of complaining about it, but I find it pretty easy to work with. I've heard (on another CB thread) that strut bolts instead of the more common strut nuts are way easier to hang with. I've never gotten to try them.

I wish we'd had it in several past venues I've worked at, specifically because we occasionally did the lighting c-clamp on 2x4 as described above. We also used to drill through the 2x4 and bolt fixtures to the wood when necessary. I'm sure someone with more structural knowledge could tell me exactly how much that de-rated the building.

Added bonus to using strut, you don't lose a few inches of hang position for whatever hardware holds up the system. For example, a pipe would have weld points on it, or a half coupler and cables to hang it, meaning you couldn't hang a fixture at that point. Seems insignificant, but those little things can make all the difference in a tight hang.

Ron: I have a scar somewhere on my scalp from exactly what you described, though the hinges weren't being used for lighting. One just got dropped on me.

 

[RonHebbard]

I second the Unistrut. I hear a lot of complaining about it, but I find it pretty easy to work with. I've heard (on another CB thread) that strut bolts instead of the more common strut nuts are way easier to hang with. I've never gotten to try them.

I wish we'd had it in several past venues I've worked at, specifically because we occasionally did the lighting c-clamp on 2x4 as described above. We also used to drill through the 2x4 and bolt fixtures to the wood when necessary. I'm sure someone with more structural knowledge could tell me exactly how much that de-rated the building.

Added bonus to using strut, you don't lose a few inches of hang position for whatever hardware holds up the system. For example, a pipe would have weld points on it, or a half coupler and cables to hang it, meaning you couldn't hang a fixture at that point. Seems insignificant, but those little things can make all the difference in a tight hang.

Ron: I have a scar somewhere on my scalp from exactly what you described, though the hinges weren't being used for lighting. One just got dropped on me.

@Chase P. A couple of points to watch with strut: If you're using standard strut nuts, pay attention to the lengths of the bolts you're using, especially if you have lamps with differing thicknesses of mounting yokes.
For examples: One venue I frequented had Altman 6" fresnels with comparatively thin yokes and Century Strand 2200 series ellipsoidals with much thicker yokes. Bolts which firmly secured an Altman fresnel to a boom T were too short to secure a Century Strand 2200 series to anything. If a bolt from an Altman was used with a Century Strand there were literally only two threads exposed to secure the Century Strand. If a bolt intended for a Century Strand was used to secure an Altman, the longer length of exposed threads would bottom out in either a boom T or a strut nut. No matter how tightly you torqued the longer bolt you were only jamming it tighter into the boom T or the bottom of the strut leaving the Altman fresnel still easily panned. Granted, there was no danger of the Altman falling but it would still rotate with zero effort. When folks would use one of the shorter bolts which worked perfectly with any of the Altman 6" fresnels to secure any of the Century Strands they barely had two threads engaged IF the boom T or strut nut were in flawless condition with zero wear on the mating threads. From memory, I believe we settled on 1/2 - 13 x 1-3/8" bolts as being a length that was workable for either fixture. And then there were the 6" Ianiro Polaris 1 Kw fresnels and 6" Ianiro Bambino 2 Kw Fresnels. It was always a game of selecting the correct length bolt and occasionally adding an extra flat washer to effectively shorten the length of a bolt.
@Chase P. Better a hinge on the head than in your eye while you're looking up.
EDIT: Added an inadvertently omitted "of".
Toodleoo!
Ron Hebbard

 

[thatactorguy]

I appreciate the feedback We try not to hang the fixture in the same location as a past hang so as not to dig farther into the lumber. Unfortunately, I can't provide photos at this point, as the ladder is put away, and the set of the show I'm directing has walls that go all the way down to the proscenium. We do, of course, safety cable anything we hang!

We're a small (138 seat) community theatre, and don't have the luxury of much money. In order to make things happen, we just do what we have to. Safety is naturally always a prime concern! The theatre (1907 L&N freight train depot) was expanded in 1990 to add the stage area that exists now; the 2x4 grid was part of that design. At the time, they were using 150W coffee can lights attached to the grid with a regular 3" C-clamp. I'm guessing it was financial limitations which prevented the installation of a 2" pipe grid. In any case, the grid is a series of 5' squares with electrics at every intersection. There are 58 outlets on the grid connected to the lighting system. Back in 1999, we started purchasing a couple of S4 jr every year or two, and are up to 24 juniors, four ParNels, a dozen UL PAR 38, and the seven PAR 64s I just bought. In total, I've bought 26 of those fixtures out of my own pocket for the theatre.

I will post up close and personal pics of how we hang our fixtures when I go up there tomorrow. Still wondering about the Eliminator C clamps and how they would attach to the grid. Perhaps I should just bore out the hole on the fixture bracket so it'll accept the larger bolt of an ETC clamp?

 

[RonHebbard]

I appreciate the feedback We try not to hang the fixture in the same location as a past hang so as not to dig farther into the lumber. Unfortunately, I can't provide photos at this point, as the ladder is put away, and the set of the show I'm directing has walls that go all the way down to the proscenium. We do, of course, safety cable anything we hang!

We're a small (138 seat) community theatre, and don't have the luxury of much money. In order to make things happen, we just do what we have to. Safety is naturally always a prime concern! The theatre (1907 L&N freight train depot) was expanded in 1990 to add the stage area that exists now; the 2x4 grid was part of that design. At the time, they were using 150W coffee can lights attached to the grid with a regular 3" C-clamp. I'm guessing it was financial limitations which prevented the installation of a 2" pipe grid. In any case, the grid is a series of 5' squares with electrics at every intersection. There are 58 outlets on the grid connected to the lighting system. Back in 1999, we started purchasing a couple of S4 jr every year or two, and are up to 24 juniors, four ParNels, a dozen UL PAR 38, and the seven PAR 64s I just bought. In total, I've bought 26 of those fixtures out of my own pocket for the theatre.

I will post up close and personal pics of how we hang our fixtures when I go up there tomorrow. Still wondering about the Eliminator C clamps and how they would attach to the grid. Perhaps I should just bore out the hole on the fixture bracket so it'll accept the larger bolt of an ETC clamp?

@thatactorguy A few comments: When you referred to a 2" pipe grid realize you're probably referring to a 1.5" schedule 40 pipe grid. Iron pipe is sized by a combination of its internal diameter and its wall thickness. 1.5" ID (Internal Diameter) pipe with a schedule 40 wall thickness is approximately 1-7/8" O.D. (Outside Diameter) and is a common size used for lighting grids and vertical lighting booms. If you inadvertently purchased 2" pipe, if it was schedule 40 its O.D. would be close to 2-3/8" and the majority of standard lighting C-clamps wouldn't open wide enough to encompass it.
I'm a big fan of Source Four Juniors. One of our local groups purchased 15 of the Junior zooms to replace their decrepit Parellipspheres and own 22 of the Junior zooms at last count and still love them.
I'd vote in favor of drilling all of your fixture's mounting yoke attachment holes to clear standard 1/2-13 hex bolts (As long as there's sufficient metal to safely do so.) so that all fixtures may conveniently be utilized with all standard C-clamps, boom T's and any other mounting accessories you may acquire.
I have no problem with sharing one safety cable between two adjacent instruments if / when you're running short of safeties but I'm a big fan of every barn door and / or top hat being safetied to its fresnel.
Toodleoo!
Ron Hebbard

 

[Chase P.]

A co-worker just showed this to me this week, out of the blue.

@Chase P. If a bolt from an Altman was used with a Century Strand there were literally only two threads exposed to secure the Century Strand.

Ron, I wonder how many threads are catching in this setup? The 2x4 has to be thicker than most yolks!

And I'm not seeing anything holding that 2x4 to anything other than the fixture. On the bright side, That's not an acoustic tile ceiling as we all first thought when we were grouped around a cellphone looking at this. The ceiling itself has a sliver of structural integrity.

Funny how this week I've had three or four conversations with co-workers about trending topics here, folks who aren't even on CB.

 

[SteveB]

Looking at the positive aspects to that photo, you don’t need to worry about the c-clamp getting over-tightened and failing !

 

[thatactorguy]

@thatactorguy A few comments: When you referred to a 2" pipe grid realize you're probably referring to a 1.5" schedule 40 pipe grid. Iron pipe is sized by a combination of its internal diameter and its wall thickness. 1.5" ID (Internal Diameter) pipe with a schedule 40 wall thickness is approximately 1-7/8" O.D. (Outside Diameter) and is a common size used for lighting grids and vertical lighting booms. If you inadvertently purchased 2" pipe, if it was schedule 40 its O.D. would be close to 2-3/8" and the majority of standard lighting C-clamps wouldn't open wide enough to encompass it.
I'm a big fan of Source Four Juniors. One of our local groups purchased 15 of the Junior zooms to replace their decrepit Parellipspheres and own 22 of the Junior zooms at last count and still love them.
I'd vote in favor of drilling all of your fixture's mounting yoke attachment holes to clear standard 1/2-13 hex bolts (As long as there's sufficient metal to safely do so.) so that all fixtures may conveniently be utilized with all standard C-clamps, boom T's and any other mounting accessories you may acquire.
I have no problem with sharing one safety cable between two adjacent instruments if / when you're running short of safeties but I'm a big fan of every barn door and / or top hat being safetied to its fresnel.
Toodleoo!
Ron Hebbard

You're right, of course! Funny story- a guy installed a pipe on the front electric that hangs about three feet lower than the grid. Makes it easier to hang on the front, and gives more options for hanging location. I'll include a pic of that along with the other pics I keep saying I'll post First attempt, he spent hours drilling holes for the hanger bolts. He couldn't figure out why a clamp wouldn't fit on the pipe. I asked him if the pipe was OD or ID. You could see him melt! Now there's ID pipe on the front row, and 36' of OD sitting outside, lol.

I've wondered about the Zooms, and will probably pick one up one of these days to try. About to place an order for a 26 degree S4 (same as our juniors) on eBay. The juniors have jumped in price since the last time I bought any! I used to find them for $185-$200, now ~$270 is the best price I can find

The yoke, while I believe is aluminum, is about 1/8" thick, and about 3/8" on either side of the factory hole, so there should be room.

 

[thatactorguy]

A co-worker just showed this to me this week, out of the blue.

Ron, I wonder how many threads are catching in this setup? The 2x4 has to be thicker than most yolks!

And I'm not seeing anything holding that 2x4 to anything other than the fixture. On the bright side, That's not an acoustic tile ceiling as we all first thought when we were grouped around a cellphone looking at this. The ceiling itself has a sliver of structural integrity.

Funny how this week I've had three or four conversations with co-workers about trending topics here, folks who aren't even on CB. View attachment 17039

Okay, when I said we do what we have to to make something work, I'll just clarify right now that we don't get THAT desperate! That is definitely an accident waiting to happen; hopefully that isn't permanent?

 

[RonHebbard]

You're right, of course! Funny story- a guy installed a pipe on the front electric that hangs about three feet lower than the grid. Makes it easier to hang on the front, and gives more options for hanging location. I'll include a pic of that along with the other pics I keep saying I'll post First attempt, he spent hours drilling holes for the hanger bolts. He couldn't figure out why a clamp wouldn't fit on the pipe. I asked him if the pipe was OD or ID. You could see him melt! Now there's ID pipe on the front row, and 36' of OD sitting outside, lol.

I've wondered about the Zooms, and will probably pick one up one of these days to try. About to place an order for a 26 degree S4 (same as our juniors) on eBay. The juniors have jumped in price since the last time I bought any! I used to find them for $185-$200, now ~$270 is the best price I can find

The yoke, while I believe is aluminum, is about 1/8" thick, and about 3/8" on either side of the factory hole, so there should be room.

@thatactorguy One of the advantages of your lower front LX pipe (as long as it can't rotate) is you can hang not only below it but also yoked up above it or yoked up stage or down stage as long as clearances permit. One of our local amateur venues never back lit claiming back lights would hang too low on their fixed height pipes and be seen by their patrons. The first time I lit a production in their venue I hung my front lights on their normal LX pipes and hung my back lights on their border pipes yoked up above their borders. Their borders barely masked each other thus hanging my back lights yoked up above their borders guaranteed they were above the sight lines of all patrons. The last theatre construction project I was on before my mini-stroke I noticed the architects had specified 2" schedule 40 welded in place for coat hangers in the common lobby serving both venues. Have you ever tried to buy a coat hanger designed to hang on 2" schedule 40?? I was the lead A/V installer employed directly by the A/V subcontractor and already had more than 40 RFI's (Requests For Information) formally documented and submitted relating to items concerning A/V thus I casually mentioned the coat check pipe to the General Contractor one day when he was passing with time on his hands but it wasn't my business to follow up on it. About a year later, days prior to opening, the city hired an FOH manager and the excrement hit the ventilator when he unpacked the high dollar, architect specified, chrome plated coat hangers and they wouldn't hang on the pipes. At this point the pipes were welded in place, ground smooth, undercoated with primer and painted. Oh how the architect tried to source hangers to fit the pipes. In the end they had to cut the pipes out and weld, grind, prime and finish new, correctly sized, pipes. Several contractors were delighted to bill for "extras". For the grand openings portable racks were rented in to support patrons attire. He who laughs last comes to mind and I'm still giggling some seven years later. The amateur group which owns 22 Source Four Junior Zooms only owns two full size Source Four 26 degrees and devote them to a pair of Rosco I-Mirrors with scrollers and DMX irises. Initially a friend sneered at the inclusion of the pricey DMX controlled irises suggesting it was better to use a narrower Source Four when required. What he was overlooking was the effective change in throw distance / beam diameter as you panned and tilted the I-Mirror across the stage from cue to cue. Guard your health and take care @thatactorguy maturing has little to recommend it.
Toodleoo!
Ron Hebbard

 

[Les]

A co-worker just showed this to me this week, out of the blue.

Ron, I wonder how many threads are catching in this setup? The 2x4 has to be thicker than most yolks! View attachment 17039

Not that this is in any way safe, but it's likely that they replaced the yoke bolt. I've C-clamped some VL500 washes in a pinch (as opposed to O-style truss clamps) and I replaced the bolts with 2" grade 8 since their base plate is pretty thick.

On further inspection, it almost looks like the spigot of the clamp passes through the 2x4. I also have to laugh because... Don't people know that you can just take the c-clamp off the light? It's not some sacred thing that must be left in place regardless of circumstance.

Just yesterday I responded to a Reddit post where someone wanted to hang a [2"] pipe. I guess they normally do lighting in a gymnasium-type facility and they were having trouble mounting their fixtures to the flat roof trusses. Somehow they were using unistrut but were complaining that while "leko clamps" will fit around the unistrut 'just fine', the O-clamps on the moving lights tend to hang at an angle.

How they were securing the unistrut, and why they hadn't discovered unistrut nuts (let alone just using beam clamps to start with) is beyond me. Some people really shouldn't leave the console, or drafting table for that matter.

I advised them that beam clamps exist, their 2" sch. 40 would be too large, and they really didn't have any business hanging a pipe based on what I had read. The post was eventually removed, so who knows how that will turn out...

 

[RonHebbard]

Not that this is in any way safe, but it's likely that they replaced the yoke bolt. I've C-clamped some VL500 washes in a pinch (as opposed to O-style truss clamps) and I replaced the bolts with 2" grade 8 since their base plate is pretty thick.

On further inspection, it almost looks like the spigot of the clamp passes through the 2x4. I also have to laugh because... Don't people know that you can just take the c-clamp off the light? It's not some sacred thing that must be left in place regardless of circumstance.

Just yesterday I responded to a Reddit post where someone wanted to hang a [2"] pipe. I guess they normally do lighting in a gymnasium-type facility and they were having trouble mounting their fixtures to the flat roof trusses. Somehow they were using unistrut but were complaining that while "leko clamps" will fit around the unistrut 'just fine', the O-clamps on the moving lights tend to hang at an angle.

How they were securing the unistrut, and why they hadn't discovered unistrut nuts (let alone just using beam clamps to start with) is beyond me. Some people really shouldn't leave the console, or drafting table for that matter.

I advised them that beam clamps exist, their 2" sch. 40 would be too large, and they really didn't have any business hanging a pipe based on what I had read. The post was eventually removed, so who knows how that will turn out...

@Les Possibly you'll be reading how it turned out in your local papers but optimistically not.
Toodleoo!
Ron Hebbard

 

[thatactorguy]

Here are photos of what I was talking about in the original post regarding how we hang our fixtures. Hope that clarifies things

 

[Amiers]

Sooooooooo.....

Cable management is a thing to be proud of and second get rid of that extension cord and clean the cob webs.

Third, to give a little bit more life to those 2x4s you could throw up some joist plates.

They show lags to attach but because you would be doing this in reverse you could get away with thru bolts on the corners and you should be fine. You could even do 1” drywall screws with washers if you didn’t want to thru bolt it.

Obviously this only helps for those that know not to crank down on the clamp.


But mainly do somehting about that cord.

 

[thatactorguy]

Sooooooooo.....

View attachment 17050

Cable management is a thing to be proud of and second get rid of that extension cord and clean the cob webs.

Third, to give a little bit more life to those 2x4s you could throw up some joist plates.

They show lags to attach but because you would be doing this in reverse you could get away with thru bolts on the corners and you should be fine. You could even do 1” drywall screws with washers if you didn’t want to thru bolt it.

Obviously this only helps for those that know not to crank down on the clamp.


But mainly do somehting about that cord.

Thank you, Amiers I like the joist plate suggestion! I just KNEW I would get busted on the cable! lol I'm LD on The Lion, the Witch, & the Wardrobe (our next production) and will address that cable That was actually done by an assistant sometime back, and I just haven't dealt with it yet. As a rural mail carrier, political season and Christmas packages ordered year round make for a worn out 54 year old man at the end of the day

 

[Les]

Don't let Clancy see this, they'll post it on Facebook .

I wonder if you could run some unistrut down the length of that 2x4. Thinking out loud, of course.