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Permalink Reply by Michael R Cossey on December 29, 2010 at 2:48pm

Do you have an electronic tuner? I use ones that tune by vibration or mic......but prefer the vib mode......mine is a clip on and I clip it onto the head......then I just move the bridge if needed ,I start with the low fattest string first and get the bridge set to that note then I mark the position with painter tape or a pencil in case it moves too much  if I need to  slanting the bridge for the higher skinny string. I now check the note of the high string and adj if needed, if string is a bit high I slant it back if too low I slant it forward till I get it to the correct note......Boy I hope that makes sense!

 

Mike

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Permalink Reply by Roadkill a.k.a. John Maw on December 29, 2010 at 2:53pm

Hey. Something I can answer (I think). If you go to the twelfth fret on each string and the fretted note matches the pitch of the harmonic then there is no need to change the bridge position for that string. In other words the strings will be in tune with each other all the way along the fret board. On some instruments this is not the case and the intonation drifts more and more the nearer the bridge you go, so an adjustment has to be made to compensate. If the instrument is fretless then a decent test is to put the slide across all the strings at the 12th fret position (octave) and if the strings are still all in tune then all is well.

 

Looking at photos it seems most common for the bridge to be further from the nut under the lower strings and the one that I have made is like that.

 

There is no calculation as such. Rather you test it and adjust as needed. If it is a one piece bridge the angle may be a slightly imperfect compromise.

 

I hope this helps and if anyone feels that I have not described this properly then please put me right.

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Permalink Reply by Paul Nelson on December 29, 2010 at 3:22pm

Thanks guys. This helps... it explains the slight intonation imperfections of my previous builds. At the time I didn't care, I was just excited it sounded as good as it did - but I'm getting a little more serious now...

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Permalink Reply by Glaze on January 10, 2011 at 5:11pm

I have an old Silvertone acoustic guitar that the wood bridge was not glued to the top.  Kind of like a Cigar box guitar.  I just put a gauge of strings I was always going to always use on this guitar(changing string gauge will change your intonation) and tuned it up with a good guitar tuner.  I kept sliding the bridge around until every string was in tune plucked open and fretted at the 12th fret (perfect intonation).  All guitars end up having the bridge at an angle or each saddle adjusted at a different lengths than each other once the guitar is setup with perfect intonation.  Each string gauge needs to be adjusted differently.

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Permalink Reply by Don Thompson on January 11, 2011 at 3:11am

This is the reason I prefer StweMac's calulator, it figures in the angle on the saddle. Mark the low string side. mark the high string side, draw a line thru them, there you are.

http://www.stewmac.com/fretcalc.html

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Permalink Reply by Glaze on January 11, 2011 at 7:03am

Don

 

That is a handy calculator.  On my old Silvertone acoustic I did not know what the scale length was when I bought it used.  

On a cigar box guitar that you build to a certain scale length you can measure where the bridge should be and just place the bridge in that position and tune the guitar up.  It's just a matter of sliding the bridge around a little to get it in perfect position where the guitar is in perfect tune on each string when plucked open and also fretted at the 12th fret on each string.  Takes some time to get it right.  

 

I love to buy cheap old Kramer guitars with original Floyd Rose bridges that have fine tuners on them.  Many times when I tune up a Kramer I buy with the strings that are on the guitar from the previous owner the intonation will be way off.  It is hard to set up a Floyd and I think some players just do not know enough about intonation.  Takes me about 20 minutes to restring a Floyd and intonate it perfectly because they are the hardest electric guitar bridge to set up perfectly.  Actually on those I usually restring the guitar, tune it up, let the strings stretch for a day and then come back and intonate the guitar after the strings are stretched in.     

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