Bolting Truss Together
- Thread starterhighschooltech
- Start date
Impacts should only be used to break truss apart. You never really know the exact torque you are getting on an impact. Also, you run the risk of crossthreading the bolt. Impacts to that rather easily. If you have ever dealt with a stuck truss bolt, you know you should avoid that at all costs.
I prefer this tool for all my truss bolting needs....
Klein 8238
Just for clarification--I think that is a Klein 3238 construction model....or is there a new 8200 series I have not seen in my catalogs yet?
-w
JD
Well-Known Member
Just for clarification--I think that is a Klein 3238 construction model....or is there a new 8200 series I have not seen in my catalogs yet?
-w
Looks more like what we used to use setting steel. This is the ONE tool everyone feared being dropped! (of course, judging by the nicks, they used to rotate and hit head down, as compared to the Edger Allen Poe position.) It always amazed me just how much weight you could move around getting the bolt in.
porkchop
Well-Known Member
Just to add some wood to the fire, while bolting together some fly track a few weeks ago one of our local workers claimed to do some work in the realm of truss engineering and went off on how since we are a touring show and we do reuse nuts and bolts all the time that grade 5 bolts would be better. I didn't really inquire as to why because I was certain that we weren't going to go buy all grade 5 stuff, but he said something about the softer metal conforming better over time and having more consistent long term rigidity. Sorry I don't have a source, just something a guy I worked with claims to have studied and had XSF and Tomcat agree with. Thoughts anyone?
I have nothing formal or official but I would never bolt anything that would fly, especially fly track, with anything less than grade eight. I saw a horizontal lifeline installation that was done with grade five eyes. With nothing more than tension on the bolts, they straightened out the eyes. I went through and replaced them pronto.
I just went through the Tomcat site and they say grade 8 only.
I just went through the Tomcat site and they say grade 8 only.
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Unless you carry around a 2' breaker bar I don't see how you could properly torque a 5/8" or 3/4" grade 8 bolt, you would have to weigh over 200lbs and stand on the end of a 12" ratchet to achieve 200 ft-lbs.
Even with a 2' breaker bar you would have to apply 150lbs. to the end to achieve proper torque.
No battery powered impact driver would get near either figure, an impact wrench might get pretty close if it's a pneumatic 3/8" or better square.
Even with a 2' breaker bar you would have to apply 150lbs. to the end to achieve proper torque.
No battery powered impact driver would get near either figure, an impact wrench might get pretty close if it's a pneumatic 3/8" or better square.
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JD
Well-Known Member
I do carry around a 18" breaker bar, and truss bolts are usually 15/16".
Every time I think that I really might be "that guy", you remind me of what I can aspire to be.
I just saw this thread now and OP made me want to find something to throw at my monitor...
CSB time:
I once had an ox of a stagehand tighten a bolt so tight he stripped the threads off leaving it stuck on. I found out during load out, and had to take 30 min to find a saw to cut it in two. Not a good time when your load out involved five guys leading crews in different parts of load out that all have to fall together near the end.
CSB time:
I once had an ox of a stagehand tighten a bolt so tight he stripped the threads off leaving it stuck on. I found out during load out, and had to take 30 min to find a saw to cut it in two. Not a good time when your load out involved five guys leading crews in different parts of load out that all have to fall together near the end.
Bill Witthans
Member
Just happened on this thread and even though its a bit old I feel its probably still checked for answers to the original question, which by the way never seemed to REALLY be answered! I have worked in the Film/TV industry for almost 40 years, put up many, many truss rigs (most of them using the gusset plate / Bolt system) and have an answer based on both field and manufacture/vendor info. I have retired from the "field" and now teach on set safety for many aspects of the film biz, one of them being rigging.
First always use manufactures / vendors supplied bolts (it’s a COMPLETE SYSTEM) these being normally grade 8, 5/8s bolts. These are installed in any direction, although most crews will do it one direction all the time for continuity and ease / speed. Use of AIR impacts for installing is a "NO, NO" because of the repetitive impact on the gusset plates and the possibility of introducing micro fractures to the plates over time. Take down, well up to you but we stress the sound of several air impacts operating as a separate danger impacting communication on set. Electric drill/driver motors are ok when set low for initial tightening. Finial tightening should always be done by hand using 15/16 socket or box end wrenches.
Now how tight, well many vendors will say only "tight, tight enough" but after speaking to several vendors 80 ft/lbs is recommended. At 80 ft/lbs other truss parts will fail before the bolts do. Now we all know that seeing a torque wrench used on truss is a VERY, VERY, rare sight (I saw it once, and it was me!) so how do we address this? Well first hand tightening will get you very close as long as you aren’t of gorilla strength and you just tighten up good and snug. A practice I have done and recommend is to have a torque wrench on the job and have your crew tighten ONE or TWO sections with it. Then have them using their hand wrenches try and match as close a possible that torque. This does not take long and gives them the “feel” of what 80 ft/lbs should be. After a while they will be able to pretty close to the 80 ft/lbs in their sleep.
A almost more important step in truss assembly is a “bolt check / re-tightening step”, meaning that as you tighten up truss the sections behind you will loosen up a bit as the whole truss rig settles in to place, so a second tightening round is a must! I was always amazed to find out how many bolts required a second snugging up after the first pass!!! Once the second pass is made most crews mark the bolts as “checked” by chalk or crayon marking the bolt tops, my crews just put a small piece of colored tape at each connection indicating that all bolts there were rechecked (faster).
I hope this helps on a practical in the field answer way as rigs keep getting bigger and more complicated as the year go on and we need to raise our awareness of safety and correct assembly to match!
First always use manufactures / vendors supplied bolts (it’s a COMPLETE SYSTEM) these being normally grade 8, 5/8s bolts. These are installed in any direction, although most crews will do it one direction all the time for continuity and ease / speed. Use of AIR impacts for installing is a "NO, NO" because of the repetitive impact on the gusset plates and the possibility of introducing micro fractures to the plates over time. Take down, well up to you but we stress the sound of several air impacts operating as a separate danger impacting communication on set. Electric drill/driver motors are ok when set low for initial tightening. Finial tightening should always be done by hand using 15/16 socket or box end wrenches.
Now how tight, well many vendors will say only "tight, tight enough" but after speaking to several vendors 80 ft/lbs is recommended. At 80 ft/lbs other truss parts will fail before the bolts do. Now we all know that seeing a torque wrench used on truss is a VERY, VERY, rare sight (I saw it once, and it was me!) so how do we address this? Well first hand tightening will get you very close as long as you aren’t of gorilla strength and you just tighten up good and snug. A practice I have done and recommend is to have a torque wrench on the job and have your crew tighten ONE or TWO sections with it. Then have them using their hand wrenches try and match as close a possible that torque. This does not take long and gives them the “feel” of what 80 ft/lbs should be. After a while they will be able to pretty close to the 80 ft/lbs in their sleep.
A almost more important step in truss assembly is a “bolt check / re-tightening step”, meaning that as you tighten up truss the sections behind you will loosen up a bit as the whole truss rig settles in to place, so a second tightening round is a must! I was always amazed to find out how many bolts required a second snugging up after the first pass!!! Once the second pass is made most crews mark the bolts as “checked” by chalk or crayon marking the bolt tops, my crews just put a small piece of colored tape at each connection indicating that all bolts there were rechecked (faster).
I hope this helps on a practical in the field answer way as rigs keep getting bigger and more complicated as the year go on and we need to raise our awareness of safety and correct assembly to match!
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