Replies to This Discussion

Permalink Reply by Scott aka Farmer Ted on November 22, 2014 at 2:06am

Hey John,

Cool little guitar. One thing I noticed is the saddle on the bridge...it is perpendicular to the strings. This is common on nylon-strung acoustic guitars. Steel string acoustics will have a saddle that is slightly angled, rather than perpendicular, to adjust for the "intonation". When steel strings are pressed down to fret a note, they tighten up sooner than nylon strings will, which makes steel strings increase their relative pitch. So each gauge of steel string requires a bit of adjustment in relation to scale length and the overall sound of each note.

Nylon strings stretch a bit more before pressing down/fretting a note. So this is why the angled saddle isn't really common in that application.

So, if it matters to you, two things to do. First, measure from nut to 12th fret and double that to determine the total scale length. Then look on Stewmac.com for the fret calculator, use it to get the fret locations, and check against your frets to see if they are spot on or not. Likely they are fine. Then, if you're using steel strings, you may need to replace the bridge with one designed for steel strings (with the angled saddle).

But all this is just hog spit if you're happy with it as it is.

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Permalink Reply by Slowpaw Steve T on November 22, 2014 at 2:48am

A very simple way to check intonation from the twelfth fret - fit your tuner in the usual way, tune each string exactly spot on ie : G D G b, then place finger on 12th fret each string in turn and the tuner  should again read G D G b but sound an octave up to your ear.

If each note is sharp slightly move the bridge to the back, if it is flat move the bridge slightly towards the neck. :)

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Permalink Reply by Ron "Oily" Sprague on November 22, 2014 at 3:18am

First off, if you have a tuner with an adjustable reference A ( which it appears you do), then correct concert pitch is A = 440 Hz, not 439. If you try to match notes at A = 439, your existing frets will indeed not intonate correctly. As SaFT sez, check your scale length first, then use the StewMac calculator to check fret distances from the nut. They should be within 0.5 mm.

Then check yer Czech to see if it has a truss rod in the neck. Check to make sure the neck is straight; otherwise, you may find that even adjusting your tuner to A = 440, some of your frets may still be slightly off. On cheaply made necks, it is common to have severe neck bow between the 14th and 9th frets. If the neck is severely bowed, crank the truss rod adjustment screw 1/4 turn at a time to reduce, but not completely remove, the bowing.

Here's one vid among many that shows how: http://m.youtube.com/watch?v=hIQXQy25qlk

Adjusting the truss rod will also allow you to set the action, or string height, for a particular saddle height.

You also need to see, as it appears from the pic, if that bridge is fixed, e.g. glued to the soundboard, or adjustable. If it is fixed, then your intonation adjustments are limited to up and down, e.g., saddle height.

Then, check your fret heights, using a small metal ruler or credit card as a rocker gauge. You may find one or more frets buzzing and or needing to be tapped back in.

The fact that you admit to partial tone deafness means you really should have someone with a good ear whom you trust check your fret intonations with you.

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Permalink Reply by Michael Fred Johnson on November 22, 2014 at 3:32am

Simply replacing the nut with a bolt will increase the distance to the first fret by half the bolt diameter

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Permalink Reply by Skeesix on November 22, 2014 at 8:00am

I think the bolts have a nice sound too. The steel of the bolt would be harder than plastic. If I'm getting all fancy and making my own nuts, I make them out of bone, which is also harder than plastic.

The thing that Michael Fred Johnson pointed out could also affect the intonation as you're making the string length a bit longer, but the frets have stayed the same. You could either make the fretboard shorter so that the apex of the bolt is in the right spot, or modify the bolt or replace it with a nut which has the apex at the end of the fingerboard.

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Permalink Reply by john mackay on November 23, 2014 at 8:44am

from the centre of the nut to the centre of the bridge is 622mm.roughly 24.5"

when I got the guitar it had a couple of steel strings on so I assumed it was a steel stringed guitar.

I'll put some nylon ones on later.

I'm not to bothered about whether it is tuned correctly here or there.

it was something that I had in mind to mess about making a 3 stringer etc.

no doubt you've all probably thought to and tried only to find it wasn't such a good idea after all but you had to do it ! to settle your mind.

what you guys have said is some thing that I can take on board for future builds. thanks.

just wanted to play practice to get my fingers to go where I want them(when I get around to it)

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Permalink Reply by Ron "Oily" Sprague on November 23, 2014 at 4:07pm

john,

I took my daughter's old Daisy Rock and stripped 3 strings off, so I could put it in Seasick Steve's Trance Wonder tuning: G, G and B, using an E string in the A position, a D in the G position and a G in the B position.

If the guitar had steel strings on it, you don't wanna replace them with nylon strings. Nylon won't give you the correct neck tension, and you may find the neck bowing on you. Better to replace them with some phosphor bronze acoustic steel strings. Most music stores will sell you single strings.

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Permalink Reply by Thumper on November 23, 2014 at 4:36pm

Slowpaw is absolutely correct,  however when plucking at the 12th fret, you're looking for a weak, harmonic sound (damp the string and pluck as you remove your finger)

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Permalink Reply by john mackay on November 24, 2014 at 3:29am

yeah but the bridge is glue on so canna move it.

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Permalink Reply by ChickenboneJohn on November 23, 2014 at 8:11pm

Michael Fred Johnson is bang on - replacing the conventional nut with a bolt has without any doubt completely screwed all your intonation  - it will play out of tune at every fret. 

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Permalink Reply by Ron "Oily" Sprague on November 23, 2014 at 11:49pm

But oddly enough, he says he doesn't care too much if it's not in tune here or there, admits to being partially tone deaf, and hasn't a clue how music is supposed to sound...seems like management material to me >:-E

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Permalink Reply by john mackay on November 24, 2014 at 3:26am

nut house more like!!

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