Bridge placement

Intonation, Compensation, Frustration
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edbanas
Posts: 18
Joined: Thu Apr 17, 2014 10:06 am

Bridge placement

Post by edbanas »

I am building a guitar with a 25.4" scale. The kit I purchased contains a bridge with the slot already cut for the saddle. According to the StuMac fret calculator, the distance from the front of the nut to the string contact point on the saddle should be 25.489" ( 647mm) for the treble "E" string and 25.614" (651 mm) for the distance on the bass "E" string. That is, the saddle at the contact point for the bass "E" string is 4 mm further away from the nut than the treble "E". My saddle slot is cut so that the saddle is oriented in the bridge only a 2 mm difference in these distances. So, do I locate the bridge so the treble "E" is at 647 mm? The bass "E" would end up at only 649 mm! Do I set the bass "E" at 651 mm? The treble "E" would be at 649 mm. Do I split the difference?and set them at 648 mm and 650 mm?

I suspect any of these options would work as long as I compensate by artfully shaving the nut and saddle. Since this is my first build, I am not certain of anything. You all have been so helpful in the past and I thank you once again.


Ed
stevegullick
Posts: 27
Joined: Thu May 15, 2014 4:59 am

Re: Bridge placement

Post by stevegullick »

John did a video on this which I folowed when doing my stewmac 000 and it is perfect. (Thanks John - I hope to be ordering a kit very soon)
MaineGeezer
Posts: 1711
Joined: Wed Aug 13, 2014 12:14 pm

Re: Bridge placement

Post by MaineGeezer »

The luthier whom I worked with building my guitar told me to set the bridge so that the center of the saddle for the first string (high E) is at a distance (scale length + 0.1") from the nut. For a 25.4" scale, set it at 25.5". Angle the saddle so the low E is at a distance of
(scale length + 0.1" + 0.125") from the nut.

He's worked out a standard compensated saddle shape that he uses for all his guitars that he feels is "close enough." None of his customers have complained, so I guess it is. Briefly, he centers the first string on the saddle, has the B string contact the saddle at the back edge, the G contact the saddle at the front edge, and the D, A, and low E contact points gradually work to the back of the saddle. I.e. draw a line from the front of the saddle at the G string to the rear of the saddle at the low E string, and have D and A make contact where that angled line intersects their position.

For the more finicky, the technique he learned at Red Rocks was to take a short snip of high E string and put it on the flat top of the saddle under the string and move it forward or backward until the compensation was correct, then shape the saddle so the string contacted at that point.

I figured out a way to do it using an electronic tuner. Tune the string to pitch with the tuner so the needle is on its mark. "Chime" the string at the 12th fret for verification -- the tuner ought to stay on the mark. Then fret the string at the 12th fret and pluck it. Ideally, the tuner should stay on its mark. If it registers high, cut the saddle so the string makes contact at the back of the saddle. If the tuner registers low, cut the saddle so the string makes contact at the front of the saddle.

As I said, I used his generic saddle shape, and it's fine. I find minimal error in the compensation. If you're a fanatic, try one of the techniques described and you may do a little better.
Don't believe everything you know.
Anything is possible if you don't know what you are talking about.
When things are bad, try not to make them any worse, because it is quite likely they are bad enough already. - French Foreign Legion
tippie53
Posts: 7011
Joined: Fri Mar 03, 2006 7:09 pm
Location: Hegins, Pa
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Re: Bridge placement

Post by tippie53 »

John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
MaineGeezer
Posts: 1711
Joined: Wed Aug 13, 2014 12:14 pm

Re: Bridge placement

Post by MaineGeezer »

Thanks John. More ideas for the next guitar!
Don't believe everything you know.
Anything is possible if you don't know what you are talking about.
When things are bad, try not to make them any worse, because it is quite likely they are bad enough already. - French Foreign Legion
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