# Nuts & Bolts



## jwl868 (Oct 23, 2008)

derekleffew said:


> One more thing: The open-end/box wrench goes on the bolt head, and the socket is used to tighten/loosen the nut--never the reverse.




derek

Why not use the wrench on the nut and the socket on the bolt head? (I didn't think there was a difference.) Does that apply to any nut-bolt assembly? Or just truss?


Joe


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## derekleffew (Oct 23, 2008)

*Re: Nuts & Bolts*

Excellent question jwl868, and worthy of the QotD forum, thus moved here from http://www.controlbooth.com/forums/scenery/9548-truss-debate-new-post.html.


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## mbandgeek (Oct 23, 2008)

*Re: Nuts & Bolts*

I'll take a stab at it. Wouldn't there be less torque required to turn just the nut thus making it more efficient? If turning the bolt head, friction from the wood/metal would come into play.


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## Van (Oct 23, 2008)

*Re: Nuts & Bolts*

For speed and mechanical advantage reasons in the first place. You should be turning the Nut, not the bolt for the second reason. Think about an auger used to drill out a post holes heck think about a twist drill bit. the edges of which can be used to "waller-out" < okie speak for enlarge> a hole. Now compare that Auger to the threads on a Grade 8 bolt going through the hole on a piece of aluminum truss. If the holes are not perfectly lined up and there is any lateral force on the bolt at all and you are spinning that bolt, rather than the nut, you are essentially drilling out the hole to a large size. If it were a piece of steel truss you run the risk of damaging the threads on the bolt, known a Galling. Nope the wrench is used on the Bolt to keep it in place the ratchet on the nut 'cause it's doing the "work". This little bit of wisdom works and should be used whenever you are assembling nuts and bolts. That's not to say never put a wrench on a nut, sometimes you can't get a ratchet where you need to be tightening a nut, that's why Open End, Box End, and Open End Adjustable wrenches were invented in the first place.


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## jwl868 (Oct 24, 2008)

*Re: Nuts & Bolts*

Thanks, Van.

[The reason I asked is that for years, I've helped assemble the booths for our church festival, and the booths are made from galvanized steel angles that are held together with nuts and bolts. 99 out of 100 times, the wrench is on the nut. There are a number of men who work for a living, and I never heard any one mention the proper technique. But at least two factors working against it: most of the volunteers don't have a deep socket; and many of the corners have a bolt interfering from a right angle, so a wrench is the only option.]

Joe


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## sk8rsdad (Oct 24, 2008)

*Re: Nuts & Bolts*

Check out the Bolt Science website for the physics of bolt versus nut tightening. In most cases that we see in theatre, tightening the nut leads to more consistent preload (torque/tightness) on the fastener and consequently fewer failures of the joint.

Thanks Van for the comments on damage to threads, or the materials being fastened. I hadn't considered it. Anodized steel wins over aluminum for hardness.


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## David Ashton (Nov 3, 2008)

*Re: Nuts & Bolts*

there is a common situation where you must tighten the bolt, and that is where you have a lock washer on the nut as turning a nut around a lock washer will chew up the nut and the surface which the nut is against.Thinking is usually better than blindly obeying "the rules"


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## WestlakeTech (Nov 11, 2008)

*Re: Nuts & Bolts*

What Derek is quoted as saying in the original post makes perfect sense and makes me wonder why I never thought of that (or was taught it) before. Granted, I've used a C-wrench before, but I think I'd like open-end better.


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## philhaney (Nov 11, 2008)

*Re: Nuts & Bolts*


derekleffew said:


> One more thing: The open-end/box wrench goes on the bolt head, and the socket is used to tighten/loosen the nut--never the reverse.




jwl868 said:


> Why not use the wrench on the nut and the socket on the bolt head? (I didn't think there was a difference.) Does that apply to any nut-bolt assembly? Or just truss?



OK, I'm going to take a stab at it:

I'm assuming (a bad thing to do) that the bolt does not move in or out of the hole during this procedure, and the head of the bolt stays flush up against whatever the bolt is going through.

In this case it is easy to keep the wrench on the bolt head, and the nut will rise up into the socket as it is unscrewed. If the tools were applied the other way around in this situation, as the nut travelled along the shaft of the bolt it would be harder to keep the wrench on the nut.

Also, to go with what other people have said, unless you must do it the other way (e.g. there is a lock washer on the nut - thanks David Ashton) you will usually turn the nut, not the bolt. And a ratchet is designed for turning and a wrench is ideal for holding.

That's my best guess. Feel free to tell me I'm wrong, but if you do, you _must _explain why.....


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