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A word of warning about brass hinges...

Last night i was alone in my work room / studio minding my own business when i was suddenly startled by a very loud "twaaannngggg..." that really made me jump...first thing i thought was the old poltergeist was up to its old tricks again (they do exist, you know...) and wondered what else i was going to hear that night....

This morning i found the culprit - my early build "The Captain" had its strings all wrapped around the neck in a most bizarre fashion, and i realised the brass hinge they were anchored to at the tail had snapped through metal fatigue, this "antique" hinge i used only on this 4 string build, another on a 3 string build, i wondered what would have happened if i'd been playing the thing and all four strings had recoiled in my face - doesn't bear thinking about, though brass is soft and i guess can only take a certain amount of strain after a few months! I guess the loud twang noise was the strings, still connected to the remains of the hinge, hitting another guitar, though sounded really spooky ...

Others may have years of use with brass butterfly hinges but i will not be using them again in future... (-;

Brass butterfly hinge taking the strain....until !

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Permalink Reply by Ron "Oily" Sprague on November 20, 2011 at 4:35am

It would make a really nice, though perhaps too small? metal bridge plate, if you cut the remaining hinge curl off...

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Permalink Reply by Mark Bliss on November 20, 2011 at 4:48am

Wow, that is a little shocker eh?

I wont get into the molecular level quantam mechanics, but note that it did NOT "unbend the curl" but indeed failed due to metal fatigue at the stress riser caused by the original bend BEFORE the curl. Sorry, just found that interesting.

Never the less, I find it a little surprising. 3 string load would have probably been ok nearly forever. Next size larger hinge would have probably been ok forever. Thanks for the stress test datum point!

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Permalink Reply by Uncle John on November 20, 2011 at 6:22am

Huh. I've had no troubles but I always use the cbg rated hinges. I notice you are a lefty. Did you use the left handed hinge?

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Permalink Reply by Slowpaw Steve T on November 20, 2011 at 8:09am

....errr....is that from the same hardware store that stocks the left handed screwdriver, hammer and spanners...? couldn't find it anywhere, luckily i'm right handed but ...my niece is ambidextrous....my uncle was cack handed, i really don't know what happened in my gene pool all those years ago... (o;

Uncle John said:

Huh. I've had no troubles but I always use the cbg rated hinges. I notice you are a lefty. Did you use the left handed hinge?

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Permalink Reply by Richard G Caudill on November 20, 2011 at 8:19am

well ,,, glad u posted this as I use a lot of em and never would a thunk about em coming loose like that ,,, I have had strings break and stick in my hands ,,, don t wanna consider and eye or cheek !!

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Permalink Reply by Printer2 on November 20, 2011 at 12:12pm

I used to break metal samples to test their strength. The hinge broke in the right spot. I find that comforting.

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Permalink Reply by Dan Sleep on November 20, 2011 at 2:26pm

Like Mark mentioned, it is interesting that it broke as opposed to the curl bending open.

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Permalink Reply by Uncle John on November 20, 2011 at 3:22pm

Steve, the smart ass comments have been fun and I am thankful for your good humor. Thanks for telling us about this. I am big on using the brass hinges for tail pieces. So far, so good with them.

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Permalink Reply by MichaelS Country Boy Guitars on November 20, 2011 at 4:17pm

Here's what I got from it, Use a bigger hinge.

Dan Sleep said:

Great information. I review it, and here is what I took away from it:

Blah blah, blahbity blah Blah blah, blahbity blah Blah blah, blahbity blah Blah blah, blahbity blah

Oily "Strat-O'-Nine-Tales" Fool said:

But in true CBN Super Advanced over-thinking mode, this interesting bit o' math is submitted for your perusal:

http://www.ganter-griff.net/web/Querverweise/EN%5Cbelscha.pdf

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Permalink Reply by Slowpaw Steve T on November 20, 2011 at 8:10pm

I should add that my brass hinges were NOT purchased from CB Gitty who stocks a similar model, mine were obtained on ebay and listed as "antique"... (-;

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Permalink Reply by Roadkill a.k.a. John Maw on November 21, 2011 at 4:38am

Most types of brass work-hardens easily. The point at which the brass was bent through almost 90º is obviously the vulnerable area. In the bending process one side of the brass has been compressed and the other stretched. If, as it is stretched it forms minute cracks then not only is there less metal supporting the load, but you have failure points.

Incidentally, some hinges that look just like this are brass plated steel. These should be quite a bit stronger. If you are not sure, try a magnet.

Dan Sleep said:

Like Mark mentioned, it is interesting that it broke as opposed to the curl bending open.

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Permalink Reply by Mark on November 21, 2011 at 5:54am

Steve, I've been looking again at the pic of the broken off piece of that hinge and something is bugging me. There's some curious discolouration and surface texture around the areas where the cylindrical part joints the flat bit. I tried enlarging with Photoshop to show what I mean...
Looks almost as if that half of the hinge was welded or soldered together. Is there any chance the halves of the hinge might have been made from separate bits joined in that way or is it definitely one of the common type where each half of the hinge is just all one piece of metal and the cylindrical bits are made by just bending tabs over.

Slowpaw Steve T said:

Found the other piece of the hinge! Comments appreciated folks, indeed a clear case of hinge misuse....amazing how much pulling power those slinkies have!!