Alright Guys and Gals,
So, I shied away from fretting an instrument based off my first and last build I tried fretting. I have been doing just fine fretless and just marking where the frets would be.
Here is my first attempt of a cookie tin guitar with a dulcimer scale. The scale length is 24 3/4" (I have a 1955 Epiphone Les Paul that is fairly spot on with that measurement). I simply transferred the measurements out and laid the necks side-by-side to compare.
I glued my frets in place, trying the bobby pin technique I had seen on here. The bridge position is fairly close to the edge of the tin where I have the bolt. The harmonics are true at the 8th fret and when in tune is sounds great chorded or open (with the exception that I think I need a few more sound holes).
My problem is, that the top string (an 'A' string from a standard pack, tuned to 'G') will not fret to the same note that the bottom 'G' string will. It's very close, but off as much as a quarter to a whole half a step. I have tried messing with the position of the bolt bridge, but once I get the top and the bottom string intonated to each other then the middle string is out.
What did I do wrong? I measured everything several times, and this time from the middle of the nut. Why would the bottom two strings fret in tune, but not the top? I am about to swear off of trying to fret anything! HELP!
The 12th fret on a guitar should fall half way between the nut and the bridge ( you may need to add a fraction more to get correct intonation especially if the string height is high). Looking at the photo I am assuming you have used for the dulcimer scale guitar frets 0 2 4 5 7 9 10 11 12 (from here http://www.cigarboxnation.com/group/dulciworld/forum/topics/fret-sp...)
so converting to your dulcimer the guitar 12th fret is your 8th fret.
Measuring the photo nut to 8th fret distance is not halfway (the bridge is too far back). You can get harmonics at several places along the string not just the 12th (guitar) = 8th (dulcimer).
If my printer has printed it correctly and not altered the ratio during the print process, the bridge needs to be nearer the centre of the tin (which will also improve the acoustic sound).
The middle string will allways be slightly out with the other 2 but by not much , look at the bridge on a 6string electric you'll see the steps in the saddles are not even , the scale should be measured from the centre of the nut if your using a bolt and the same with a bolt bridge , if your managing to get top and bottom strings in tune there can't be too much wrong with it as already said if you have a very high action fretting the strings will pull it out of tune
Here's a pic from my last build with a hardtail bridge you''l see the saddles are not in a straight line
The action is about 3/8" at the nut. I am using 11 gauge electric strings (all I had laying around). I reworked the bridge a bit. The sound is better, but the notes fretted are not (still the same issue with the top string). It is all the way up and down the neck. Do you think it could be the angle coming from the bridge? There is not much of a downward angle like on a guitar; it's fairly flat (maybe around 5-10 degree angle).
From the nut to the 8th fret is around 12½". Measuring from the 8th fret down the bridge should be at the edge of the tin (as I thought). That's probably why re-working the bridge helped the sound quality. I am able to get clearer harmonics at the 4th and 8th frets. The harmonics are spot on.
I will attach a better picture when I get a chance.
Could you confirm that the intonation is fine with a slide, but not when you fret the notes?
The nut action at 3/8" is nearly 10mm... if you're trying to fret that it will throw the notes out completely. 1mm is more like it. In order to fret a note you are effectively stretching a string... which will cause it to sharpen. Is there any way you can either fit a different nut (zero fret or similar) or sink the bolt into the neck to make it lower?
A picture from the side, at a higher resolution if poss would be really helpful.
Very confusing...you can intonate the top and bottom strings fine, but the middle string is close to 1/2 step off? I'm not sure what could explain that.
Thanks Kid. Yeah... I messed up on this neck when making it for a box build (got in a hurry and misread my measurements for the box and didn't take into account the lid). I typically try to do the same with the bridge position as you do, but was hoping to be able to salvage a good piece of red oak that was already cut and sanded.
Thanks for the suggestions. Gives me something to try rather than having to start over with the neck. :-)
I realise you have measured and remeasured but looking at your photo it looks like the bolt bridge is too far back
Measuring from nut to the 8th fret and then adding this length again I get the bridge to be in the centre of the tin.
Dividing the nut to the bridge bolt length I get the midpoint at the "X" (which would be around the 15th or 16th fret of a guitar and between dulcimer frets 9 and 10).
Perspective of the image is off in the attached pic (quick shot from a bad camera phone). I saw what you were saying originally and thought I had really screwed up somewhere. I went home after work and remeasured. My measurements are accurate. I will repost some better pics once I am able (probably tonight).
I will take a side shot of the string action as well. It does sound like the nut is probably my problem. To clarify for some who are confused, the top string won't intonate properly when chorded, while the middle and bottom strings will. I didn't think to try it with a slide, but will try that as well to see.
Thanks for all the help and suggestions!
Here are the pictures I promised. I had issues with my card reader and a new camera card. The action at the nut was actually closer to 3/16" to 1/4" (not sure where I got 3/8" from).
I tried replacing the bolt at the nut with a much smaller machine screw. I then had to switch back to the bolt I originally used for the bridge (the rolled up piece of tin seen in the pictures looks cool, but started causing some strange string vibrations once the nut was switched). The results were very promising.
Thanks for all the help. It looks like I just need to sink the original bolt (nut) down into the neck and I will totally be in business. I'm so glad I tried this with a generic tin I found and not one of my good ones. I have learned a lot with this build and have a feeling I still have more to learn from it.
Thanks again! I will post a video once I get things the way I want them with it. :-)