Bridge angle

Why is the bridge on a guitar not perpendicular to the strings? And how does one figure out what angle it should be at on our home made builds? It doesnt seem to be that way on a ukulele. —B

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  • Intonation comp. for the thickness of the wound strings.
    Strobe tune and thats what you get..an angle.
  • From my end of things, I can say that I've always appreciated having more control over the instrument, which is especially true as I learn more about playing the guitar rather than just building it. That's why we all love electric guitar bridges: it's so easy and fast to adjust both the action of the strings and the intonation of each saddle. To that end, my acoustic bridges always employ a floating saddle and I try to provide about 1/2" of travel in either direction on the flat area of the bridge itself. That way the player can make adjustments as needed. Some guys go way overboard with this stuff. Martin Oakham, a well known and respected luthier, insists that you hold the guitar in a playing position as you adjust intonation because the stress placed on the neck (via gravity) will be more representative of when you're playing.

    There's a lot of math that goes into explaining why proper intonation is important (I don't understand a lot of it myself) but the best explanation I've ever heard is that no matter what you do, you're only ever going to have one portion of your scale play accurately at any time. If you have everything up at the low end playing perfectly, you'll find that notes up at the high end are a little bit off. Setting your intonation to be as near perfect as possible at the 12th fret (the exact middle of the scale) is a compromise that attempts to minimize and spread this error out as much as possible over the entire scale.

    Everything about a guitar is a balancing act. What you're dealing with is essentially an imperfect instrument that we then try to coax and massage into playing perfectly. In order to attain absolute mathematical perfection, you would need to render the guitar unplayable - as in the strings would have to be laying right on the fingerboard, or even better, notes would have to be created by pinching the string precisely in open space rather than fretting it against a hard surface. Both methods are obviously impossible or at least impractical, so we compromise by raising the strings over the fingerboard and fretting them back down onto it. You pull the string sharp when you do this, though, so in order for the fretted string to be pitch perfect, the open string needs to be a little flat, or vice versa, etc, etc, infinity.

    I once dedicated some serious time to contemplating the mechanics of how this all goes together and found that I had lost about 45 minutes before I knew what happened. I'm not making that up. You'll find that this rabbit hole goes deep.
  • Tim said:
    you make cbg builders sound like a bunch of monkey see monkey do morons.

    Well? how did you get the idea to build your first own CBG? The majority of members here, are not high tech luthiers, or even guitar players. The best part of CBG's that that you don't need to be, and that lets anybody, even morons like me, feel like we have created something rewarding.
  • Most CBGs have a rather short scale, and the strings are only rarely pressed down to the fretboard as most folks play them with a slide. This means much less tendency to go sharp or flat as you play up and down the fretboard.

    Setting up a regular guitar for "perfect" intonation on all strings and at all positions is a compromise at best; though it's also true that the vast majority of musicians and listeners can't hear the tiny variations that exist.
  • you make cbg builders sound like a bunch of monkey see monkey do morons. and they arn't im sure there are quit a few members here who could build and setup some very fine guitars but choose to build cbg. and they know perfectly well why the bridge is at an angle and how to get the right angle.

    Mortimer Snerd said:
    Precision bridges have adjustable saddles for intonation adjustments. CBG builders without precision bridges, guess by angling the bolt/ink pen/ stick/ screw/bridge, as an attempt to guess at correcting intonation. Another person see's this, and copies it, and the next guy see's it and it just goes on and on without anyone really knowing why it is done. .
  • What Diane and Mort Said ...
  • I don't glue my bridges down. I let them float, and then I figure I can move them if I someday decide to put on different strings. A pencil mark is there for ballpark location in case the bridge travels for some reason.

    I don't expect my guitars to be flawless, but I want them to play as well as they can. The floating bridge is pretty simple, and it works well for me. (also, skootching back the bridge a tiny fraction - there is a thread somewhere about that)

    I try to make each instrument a funky little jewel. So while there are no rules per se, my rule for me is to try for the best sound and playability out of a stick and a box.

    Brendan deVallance said:
    Thanks for all the great info. I have a fear of gluing anything down on my guitar. Now I know why. My bridge is just sitting on top and it does sound pretty good as is. I have been contemplating ways to affix it and allow for adjustments, but that alludes me at this point. Ahhh, the next one . . . .
  • I like to leave everything adjustable as well. I don't glue the box shut and always have bolt on necks, because I hate the idea that all the bits will never be adjustable!

    Brendan deVallance said:
    Thanks for all the great info. I have a fear of gluing anything down on my guitar. Now I know why. My bridge is just sitting on top and it does sound pretty good as is. I have been contemplating ways to affix it and allow for adjustments, but that alludes me at this point. Ahhh, the next one . . . .
  • Thanks for all the great info. I have a fear of gluing anything down on my guitar. Now I know why. My bridge is just sitting on top and it does sound pretty good as is. I have been contemplating ways to affix it and allow for adjustments, but that alludes me at this point. Ahhh, the next one . . . .
  • Usually i don't fix the bridge down so it remains adjustable.
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