Where do you get a fret scale ruller from in the UK?

[BUGGY (C)]

Hi

Does anyone know where to get a fret scale ruler in the UK from

and which is the best and typical scale to use.

 

Thanks for any help

BUG

 

[BUGGY (C)]

Thanks Mike and Diglydog... the scale ruler I have doesn't show bridge position

is there a rule for this? or just where it works to get the 12th fret harmonics right?

 

[Michael Fred Johnson]

The 12th fret is half way between the nut and saddle though usually the saddle is moved a couple of mm further away to build in compensation.If you look at alot of guitars you will see the saddle is not parallel to the nut increasing the string length across the bridge .The lowest string being the longest.

Hope this is clearer than mud

[BUGGY (C)]

Mike
Is there
Any maths on this?
Lowest = fattest?

[Diglydog]

Yes, as Michael said, the nominal scale length (nut to bridge) is twice the distance from the nut to the 12th fret. That's a good start point, then use 12th fret tuning to position the bridge accurately. Then get a tuner (or a free tuner app for your mobile phone) and check the other frets.

Then start pulling your hair out as various frets go in and out of tune as you move the bridge.  I had a ponytail before I started this lark :-)

[BUGGY (C)]

Aha
Is the scale dimension the overall length distance from nut
To bridge
And how do you work out the bridge angle then?

[Diglydog]

Nominally, yes, a 25-inch scale measures 25 inches from the nut to the bridge, 12.5 inches to the 12th fret. The frets are obviously fixed but bridges can be moveable.  Start by marking a small dot on the box at the scale length and put the bridge there. You'll probably have to move it a bit further away to get the intonation right. Lower strings want to be a tiny bit longer and wound strings are different to plain. If you look at this pic of a Tele bridge, you'll see 2 sloping 'sets' of 3 bridge pieces, one set plain, one set wound.  They overlap, which is a bit of a nuisance when you're trying to accommodate plain and wound on a single straight bridge :-\

There's probably lots of theory and maths but I don't have that knowledge, just a bit of experience from a small number of builds.

The best advice I've seen on here is "don't over-think it". I'm resorting to that more often as the days go by.

[BUGGY (C)]

Thanks Diglydog... yeh I have set up a few like this... and kindof wondered why my bridge bolts were working at best at an angle...I Don't get the math's why though? 

I generally suck it and see and move till I get it right... maybe this is why so many you see have adjustable bridges and angles.etc.

As you also see compensated bone bridges.. but if this is a variable how can a preset bone bridge work?

I am intrigued now to why...presumably the thickness must affect its correct intonation point?

or is it becase thinnner strings sit higher in the nut and hence may be slightly different lengths?

You can't beat a bolt and nut for ease...

Does anyone know with a stewmac scale if the ruler is the length of the nut to bridge point?

or they rely on you knowing the scale distance? 

 

[BUGGY (C)]

http://www.lutherie.net/saddle_angle.html

[BUGGY (C)]

http://theunofficialmartinguitarforum.yuku.com/topic/113453

"In a nutshell, compensated saddles are adjusted such that the open note and the fretted note at the 12th fret are the same note but an octave apart. There are many other issues of construction and adjustment that effect overall intonation of the fingerboard but the length of the string at the saddle is adjusted to compensate for how much a given string goes sharp as it is pushed down to the 12th fret. Usually each string requires a different amount of compensation. If a string is sharp at the 12th fret when compared to the open note then it is made longer at the saddle to flat the intonation to bring the string in tune. Conversely, if the string is flat at the 12th fret when compared to the open note then it is made shorter to sharp the string's intonation to bring it in tune. In general the bigger strings go sharper so require more length except when we go from the biggest plain string to the smallest wound string. In your typical acoustic set the G string is bigger in gauge than the B string but requires less compensation because it is a wound string. That's where we get the pattern of two and four. The B is behind the treble E but the G is ahead of the B but then usually each successively bigger string gets longer. I hope that helps a bit."

[BUGGY (C)]

"Real strings don't work like the strings they talk about in Physics 101. In particular, real strings have some stiffness, and they change in tension when they are displaced, which the 'ideal' ones don't. As a result, an 'ideal' string would play perfectly in tune on every fret of a solid body guitar if the frets were placed accurately, but real strings can't.

Depressing a string down onto a fret stretches the string a little bit, and this raises the pitch. One way to compensate for this is to make the played length of the string, between the fret and the bridge, a little longer than it 'should' be. In theory you probably should use a different compensation for each note on the string. In practice, a single saddle setback per string usually works reasonably well PROVIDED the fretboard is flat and the action at the nut is low. 'Relief': that little bit of dip in the fretboard around the 6th or 7th fret, allows you to play with more dynamic range, but also messes up the intonation because the string is stretched more than it 'should' be there. A high nut causes more of a tension rise on the lower frets than it 'should'.

The amount the pitch rises depends on the material, construction, and tension in the string, assuming you're displacing it the same distance in the same place. Basically, the higher the Young's modulus of the string, all else equal, the more the tension will change for a given displacement. Similarly, the thicker the part of the string is that's taking the tension (the core of a wrapped string, for example), the greater the tension change.

The thing is that, for a given string, the amount of the tension change will depend on the length and displacement, and not on the initial tension. If a given displacement results in the tension rising by a half pound, you'll get the same rise in tension whether you started off with two pounds of tension on the string or ten. Obviously, the rise in tension will cause a much greater pitch change in the slack string than in the tight one.

If you think about all of this, you'll see why a plain steel G string 'bends' more than a wrapped one. They might start out with about the same tension, but the tension change for the plain string is much greater because it's a lot thicker than the core of the wrapped string. In effect, the plain string is at a much lower tension relaive to the load it _could_ take, and that's another way of looking at it.

Nylon strings stretch so much (have such a low Young's modulus) that the tension doesn't rise a lot when they're depressed to the fret, even though they usually have higher action. That's why you often don't see any compensation on Classical guitars. The exception there is the G string, for the same reason plain steel Gs tend to bend, and need more compensation.

Stiffness in the string causes all of the partials to be shifted upward in pitch. The shift is a function of how much the string has to bend to form the wave: higher partials involve more bending (at a given amplitude), so they are shifted upward more in pitch. My understanding is that our impression of the pitch of a string depends on a sort of 'weighted average' of all the partials we hear. The more these are shifted by string stiffness, the higher our impression of the pitch of the string would be, if that's true. Frankly, I'm not at all sure how this factors into compensation, but it should. One could surmise that it would increase the needed saddle setback, since stiffness becomes more of a factor as the string gets shorter.

There's another way in which 'ideal' strings differ from 'real' ones: ideal ones have fixed ends. The bridge (at least) on an acoustic guitar moves; if it didn't you would not hear anything. This can shift the pitches of string partials, particularly when they are close to the frequencies of major resonances of the top or air of the guitar. Since these resonant pitches vary from one instrument to another, both in pitch and strength, the effected notes will be different too. This is one reason it's almost impossible to make a guitar play 'in tune' on every string and every fret. If you then add in the compromises involved in 'equal temperament', which puts all the intervals except the octave a little bit 'out', you'll see why some people are never happy with their tuning. And then there are old strings...".....

 

Found this above...does this help

[BUGGY (C)]

http://en.wikipedia.org/wiki/Young's_modulus

[BUGGY (C)]

So .... slide your bridge around untill it sound ok!!

or fit an adjustable guitar bridge....