Methods of Splicing Pipe

gafftapegreenia

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I believe JR Clancy was the rigging vendor for the Kaufmann Center, and they are certainly no stranger to custom built products.
 

BeeHive

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I would suggest against using threaded couplings such as the one pictured (b) in derekleffew's post. I have them on the battens in the theatre I work at in Excelsior Springs. About a month ago the coupling broke
 

philhaney

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I would suggest against using threaded couplings such as the one pictured (b) in derekleffew's post. I have them on the battens in the theatre I work at in Excelsior Springs. About a month ago the coupling broke
I agree. In his "Stage Rigging Fundamentals" class, Jay Glerum specifically speaks against using threads and couplings, and demonstrates why.

His solution is similar to the expanding splice (d) in Derek's post, except he recommends pipe that just fits inside the batten, going in 12" to 18" each way, with two bolts and nuts through both pipes on each end.

That's how we couple batten pipes at the venue where I work.
 

venuetech

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I don't think you would call this splicing the pipe, but at a high school I did a show at, they had a few battens that just a long piece of smaller pipe fitted in the batten and when you wanted it longer for what ever reason, you could just loosen the bolt and slide it out. then tighten the bolt again. Is that something you would normally do?
I had this setup in a venue i worked in a few years back. very nice for the legsets. it was a newly renovated space then and had a very good rigging consultant from the Seattle area.
 
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BillConnerFASTC

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Clayton NY 13624
Just google steel tubing or 1 7/16 round steel tube and you'll find a lot. I'd never use threaded couplings - no structural data or backup at all. The expanding type have generally been tested and rated and shown to be as strong as the basic pipe. While the basic steel tube - I like bolts to make it easy to disassemble but M Powers roll pins are probably fine - no personal experience - is what I use most, the expandable ones are nice for more finished spaces and really make flat pipe grids much more feasible - with all intersections shop fabricated.
 

BillConnerFASTC

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I spoke with the guys at J.R. Clancy. They make them out of 1 9/16" DOM Mechanical Tube. (11 gauge) Schedule 40 pipe is 1.61" ID so this fits perfectly.
For a splice or for the extender - or both? Do you know if the extension at Kaufman is captive? ie: you can't pull it out? (or it can't fall out). When I include this feature I make sure they are captive.
 

Jimmymise

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I doubt its captive. But we spray paint the last few feet of our extensions fluourescent orange so we know we are getting to the limit. I'm not sure how you could make this captive since it fits perfectly. They use the 1 9/16" x 11 ga. DOM tube for splicing and extenders.
 

teqniqal

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Dallas / Fort Worth, Texas
As mentioned, standard pipe sizes won't provide a snug fit for internal splicing sleeves unless they are milled-down:
  • 1.5" i.d. Schedule 40 pipe requires a 1.25" i.d. Schedule 160 pipe be milled-down to ~1.59" o.d. to fit inside and provide the same or greater wall thickness (i.e. strength). Alternatively, you can buy 0.150" thick walled DOM that is 40mm (1.625") o.d.
  • 1.5" i.d. Schedule 80 pipe requires a 1.25" i.d. Schedule 160 pipe be milled-down to ~1.48" o.d. to fit inside and provide the same or greater wall thickness (i.e. strength). Alternatively, you can buy 0.203-220" thick walled DOM that is 1.375" o.d. (but the fit is a bit looser than the milled Schedule 160).
You have to check the materials being provided to you by your rigging supply house for internal splicing sleeves - many are too loose (rattle around) and/or too thin (too weak).

My vote goes to the cross-bolted 18-24" internal sleeves. Cap the exposed thread ends of the cross-bolts with an acorn nut to reduce the flesh snags.

Helpful hint: If you apply retroflective number tags (like used on houses and mailboxes, about 1.5-2" tall font) at the ends of the battens, facing downward, you can spot them and identify them up in the fly loft with a flashlight from the stage floor.
 

Luke82

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Reviving an old discussion... In the context of splicing battens in either a pipe grid (lots of hanging supports and cross-over clamps at the grid intersections) or in long theatrical battens: has anyone used power-actuated fasteners (PAFs, such as Hilti or Ramset) to secure the outer pipe batten to the internal spline pipe? (Method C as discussed above.) I have often used bolted internal splines with four bolts per splice to join battens like this, especially in weight-bearing battens. I recently came across a pipe grid that used PAFs instead of bolts to secure its spline. It seemed very strong and quite rigid.

I am interested if anyone has done any engineering analysis on such a splice. According to the Hilti website, there are PAFs are rated for use in steel of the type used in Schedule 40 pipe and in the spline pipes.
 

teqniqal

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Dallas / Fort Worth, Texas
Reviving an old discussion... In the context of splicing battens in either a pipe grid (lots of hanging supports and cross-over clamps at the grid intersections) or in long theatrical battens: has anyone used power-actuated fasteners (PAFs, such as Hilti or Ramset) to secure the outer pipe batten to the internal spline pipe? (Method C as discussed above.) I have often used bolted internal splines with four bolts per splice to join battens like this, especially in weight-bearing battens. I recently came across a pipe grid that used PAFs instead of bolts to secure its spline. It seemed very strong and quite rigid.

I am interested if anyone has done any engineering analysis on such a splice. According to the Hilti website, there are PAFs are rated for use in steel of the type used in Schedule 40 pipe and in the spline pipes.
I have seen this done. I don't like it because it makes servicing / removing the pipe grid VERY difficult. I think it is just lazy installation with total disregard for any future work that may have to be performed.

Strength-wise, I think the strength of the joint lies in the splicing pipe dimensions, not so much in the fasteners, as they are just there to keep the pipes from slipping apart.
 

Luke82

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Funny thing... we THOUGHT they'd be impossible to disassemble. Turns out a claw hammer and some whacks to set it on the nail head and they pull out without too much fuss.
 

MPowers

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Jan 11, 2010
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Des Moines, Iowa
As mentioned, standard pipe sizes won't provide a snug fit for internal splicing sleeves unless they are milled-down:
  • 1.5" i.d. Schedule 40 pipe requires a 1.25" i.d. Schedule 160 pipe be milled-down to ~1.59" o.d. to fit inside and provide the same or greater wall thickness (i.e. strength). Alternatively, you can buy 0.150" thick walled DOM that is 40mm (1.625") o.d.
  • 1.5" i.d. Schedule 80 pipe requires a 1.25" i.d. Schedule 160 pipe be milled-down to ~1.48" o.d. to fit inside and provide the same or greater wall thickness (i.e. strength). Alternatively, you can buy 0.203-220" thick walled DOM that is 1.375" o.d. (but the fit is a bit looser than the milled Schedule 160).
You have to check the materials being provided to you by your rigging supply house for internal splicing sleeves - many are too loose (rattle around) and/or too thin (too weak).

My vote goes to the cross-bolted 18-24" internal sleeves. Cap the exposed thread ends of the cross-bolts with an acorn nut to reduce the flesh snags.

Helpful hint: If you apply retroflective number tags (like used on houses and mailboxes, about 1.5-2" tall font) at the ends of the battens, facing downward, you can spot them and identify them up in the fly loft with a flashlight from the stage floor.
Funny thing... we THOUGHT they'd be impossible to disassemble. Turns out a claw hammer and some whacks to set it on the nail head and they pull out without too much fuss.

Luke, “nail head” ? Really? You know there’s a tool for that called a pin punch.
Tiqnigal said “...cross-bolted......acorn nuts......” excellent method. When I was installing rigging systems, we used 1/4” roll pins, cross pined in the same manner as cross bolts. Completely smooth. Requires a good shop set-up to pre drill the holes accurately.
 

Luke82

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Luke, “nail head” ? Really? You know there’s a tool for that called a pin punch.
Tiqnigal said “...cross-bolted......acorn nuts......” excellent method. When I was installing rigging systems, we used 1/4” roll pins, cross pined in the same manner as cross bolts. Completely smooth. Requires a good shop set-up to pre drill the holes accurately.
Well, the point of using PAFs to secure the internal spline is to avoid any shop pre-drilling... because we need to do it all on-site to avoid the cost of shipping the steel around, and to avoid the hours of labor involved in driling holes in steel. With PAFs there's no pre-drilling or even much measuring. Point & shoot and your 24" spline is secure. They can be removed if you screw up or need to dis-assemble the batten later. I'd just like to know if anyone has had experience with them. (Thanks, Erich!)
 

MPowers

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Des Moines, Iowa
I did understand your initial use. Never tried that, I would need to see it in action to make any kind of personal opinion. How do you align to get a 90 degree entry angle? Ever have any issues with a missed shot or .....?
As to my method. Re: shop time. The pre-drilling is done months or weeks in advance during slack times. Re shipping, the company owns trucks to transport rolling tool boxes, pipe, etc to a job site. So for us. That worked.
 

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