Rebar harmonic. .. ?

Volitions Advocate

Hero Member
Alright I work for a Steel fabrication warehouse and My job is rebar.

Today i was looking around for a scrap piece of rebar to use as a lever for something and as I picked it up i hit it on the track for our crane and it made this ringing noise.  So I reached up and grabbed the end of it and it stopped vibrating.

So I thought for a second and wondered why on earth it was vibrating int he first place since I was holding on to it already.  And the answer came to me clear as day in only the way a complete guitar nerd would figure it out.

I was holding the bar right on the 12th fret harmonic.....    Yep I'm a guitar nerd.

I had my hand pretty much right in the middle of the bar.  So i tried it again. and it rang even though I was holding it. So I moved my hand a few inches one direction and struck the steel rail again.  and it went clunk with no ringing.
I dont know  if that means i'm an idiot for not realizing that the same physics can be applied to all sorts of things that are usually applied on gutiar strings. or If i'm just wrong and that they'r enot related at all.

Regardless.. I'm still a guitar nerd.

What do you guys think?  Had any experiences like this where something totaly non guitar related got your mind turning and gave you an answer based on your knowledge of guitar physics?
Strangely enough, I've had the same thing happen to me with rebar.  :icon_scratch:
I think I'm shutting down my PC and taking the rest of the day off.  I need to go think on this.

:toothy11:  j/k  :toothy12:
You know,  tried the same thing on my younger brother...
It made an awful noise until I put my hand over the top end of it.
Yep, this works with guitar strings, rebar, pipes, everything.... even air.... try playing a bugle.  You'll notice that all the notes you can hit are harmonics of the fundamental note.  All brass instruments can play off harmonics, that's how you get higher notes on a trumpet.
sorry, I had to say that. It sounds too much like conversations Ive had with friends after we scored some. :icon_jokercolor: and then afterwards :glasses9:

The 12th fret harmonic can be observed quite easily on the Fender .550-.290 "Vintage Rebop-A-Rebar Bass" string set.
not sure about the imperial measurements but it was a 15M bar.  thats 5 Bar for you yankees.

  15mm / 25.4 = .590 ...  hmm...  good enough for the G string maybe?
We stock as high as 35M for you Six String virtuoso's
DocNrock said:
-CB- said:
The 12th fret harmonic can be observed quite easily on the Fender .550-.290 "Vintage Rebop-A-Rebar Bass" string set.

Can you string a bridge with those?

Man you can string the Sydney Harbour Bridge with those  :toothy11: :toothy11: :toothy12:
TimC said:
Here's a guitar trivia question: How many octaves are found on a guitar string?

an infinite number? right? Technically isn't every note being played at the same time just at different volumes?
Yes, an infinate number of octaves in theory.  I never thought of every note being there too in a vibrating string.