Hello everyone. I just recently finished my first 4 string CBG build, You can see the uploaded photos my page for reference. Overall I think the project went well for a first build, however...
I've attempted to set up the string height for both slide and fretting, and with the floating bridge, I've gotten the harmonic intonation correct at the 12 fret. The problem I'm running into is fretting the strings closer to the nut causes them to run sharp, while fretting closer to the bridge runs flat. If you reference the pictures, you can see that I used bolts for both the bridge and nut, and the fretboard I purchased from CBGitty. The strings do run lower to the frets at the nut, as my adjustment point has been the bridge, but I can remove the nut and make a taller one if that is the problem. Also, I'm curious if the center point of the nut (bolt) may be too far from the first fret due to the width of the bolt. Basically, I'm stuck. Any input on this would be appreciated.
Just figured out I could add photos to the discussion.
A taller nut would make the problem worse since you would need to press the string down even farther causing it to go even more sharp. But if you are setting it up with high action in order to play slide I think the compromise is having to have less than perfect intonation when fretted.
How high are the strings at the nut and 12th fret?
Hard to tell at this angle but it looks like the nut is set with the bolt against where a standard nut would go so the string break point is roughly half the width of the bolt out. Either trim the fretboard so the strings last point of contact is where the end of the fretboard is or use a square nut.. I use plastic chopstick.
The action at the nut might also be a little high. I check this by pressing the strong between the second and third fret. Old time wisdom states if the gap between the string and the first fret is about the thickness of a cigarette paper it's perfect.
Good eye Titch. I was just looking at the pics again and wondering about the placement of the nut.
Ken, in addition to what Titch said about the nut height I would check the fret measurements for the scale to confirm the frets are in the correct location for the scale. I had to replace a bolt with a corian nut that I tapered to get the correct first fret distance for a friend's build. He had purchased the CBG as a kit with the frets already installed. Also, if you move the bridge on just a slight angle you might be able to improve it. Bottom line though is don't sweat it too much if it's close. Just play fast and no one will know.
Quote " The problem I'm running into is fretting the strings closer to the nut causes them to run sharp"
Because the Nut / Nut Slots are TOO high so when you press a sting on frets 1 -5 you are actually bending the string causing it to be out of pitch.
So what Scale length did you use?