I agree. In his "Stage Rigging Fundamentals" class, Jay Glerum specifically speaks against using threads and couplings, and demonstrates why.
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.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?
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.
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.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.
As mentioned, standard pipe sizes won't provide a snug fit for internal splicing sleeves unless they are milled-down:
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).
- 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).
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.
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!)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.