#1
The last few step on my question for guitar knowledge.

When my knowledge base is complete, and my wallet is full, I will start work on my first guitar, building it completely from scratch.

Now, there are still things I don't understand, mainly the things mentioned in the title.


Ok, to start from the beginning.

A) I want a 25-1/2" scale length. This is from the top of the nut to the point on the saddle where the string stops vibrating. Basically the length of the vibrating string. It is neccessary to get millimtre perfect fret spacing, and ultimately if you get the scale length a bit wrong, everything screws up. Is this correct?

B) Assuming that this is correct, How exactly do you make sure that this measurement is exactly correct while installing the bridge. Is this information including in some sort of instruction manual usually included with the bridge? Because it seems quite difficult to put the bridge in the exact right place to get the correct scale length.

If possible, could someone either go through the process step by step with me, or link me to some sort of step by step scale length-bridge related tutorial.

C) I was told at some point that if I was making everything myself, scale length wasn't important. Since I don't understand it anyway, this didn't mean much to me.

D) If you get the scale length a bit out, and you put the frets in for a 25-1/2" scale length, but you actually made a 25-3/4" scale. Is it just a matter of moving the saddles forward by the difference?

E) On a tunomatic bridge the saddles are at an angle. Doesn't this mean the the vibrating E6th string is larger than the vibrating e1st string? and wouldn't that also mean that the frets should be spaced a bit further apart?

F) Does a tunomatic bridge require a neck angle? I don't feel up to making one, so could someone list bridges that don't require a neck angle. I don't want to route out a tremolo cavity btw.

Thanks for reading, hopefullly I should be able to make a guitar soon XD
#2
Quote by psyks



Ok, to start from the beginning.

A) I want a 25-1/2" scale length. This is from the top of the nut to the point on the saddle where the string stops vibrating. Basically the length of the vibrating string.


Ok, lets stop you there. Incorrect. The scale length is the THEORETICAL string length. It is used to position the bridge, and the fret spacing. The VIBRATING string length is ALWAYS longer than the SCALE LENGTH. It is longer, due to the fact we need to COMPENSATE (intonate) for the fretting action, when playing a note.

Quote by psyks

It is neccessary to get millimtre perfect fret spacing, and ultimately if you get the scale length a bit wrong, everything screws up. Is this correct?

The scale length is critical. It doesnt matter what the number is, it matters that everything relates to it. If one fret is half a millimetre out, it will not play in tune.


Quote by psyks

B) Assuming that this is correct, How exactly do you make sure that this measurement is exactly correct while installing the bridge. Is this information including in some sort of instruction manual usually included with the bridge? Because it seems quite difficult to put the bridge in the exact right place to get the correct scale length.

If possible, could someone either go through the process step by step with me, or link me to some sort of step by step scale length-bridge related tutorial.


Buy a book. Dont try and save $30 (or less), when you will not get out of building a guitar (from scratch) for under $400. The book is the FIRST tool you should buy.


Quote by psyks

C) I was told at some point that if I was making everything myself, scale length wasn't important. Since I don't understand it anyway, this didn't mean much to me.

The scale length is critical. It doesnt matter what the number is, it matters that everything relates to it. It could be 20" or 5000", as long as everything relates to that chosen number.


Quote by psyks

D) If you get the scale length a bit out, and you put the frets in for a 25-1/2" scale length, but you actually made a 25-3/4" scale. Is it just a matter of moving the saddles forward by the difference?


Yes in theory, but it doesnt work like that in practice. The saddles wont have enough movement forwards. Remember, the saddles need to be MOVED BACK to a LONGER distance than the scale length. Ask yourself, if that is the case, why do you even need ANY forward movement at all? You dont. So dont place your bridge expecting to have very little, or no forward movement of the saddles.


Quote by psyks

E) On a tunomatic bridge the saddles are at an angle. Doesn't this mean the the vibrating E6th string is larger than the vibrating e1st string? and wouldn't that also mean that the frets should be spaced a bit further apart?


Read my first response. Scale length and intonated playing length are two different things. You need to get your head around this before you can build a guitar 'that works'.


Quote by psyks

F) Does a tunomatic bridge require a neck angle? I don't feel up to making one, so could someone list bridges that don't require a neck angle. I don't want to route out a tremolo cavity btw.

Thanks for reading, hopefullly I should be able to make a guitar soon XD


It usually needs a neck angle, but recessing it into the body means it doesnt. The ONLY way you can work out if a guitar neck needs to be angled or not, is if you have drawn a plan. If you cant be bothered doing that, dont bother starting to build.

By the sounds of your post, you need to learn more about guitars. Ive taught hundreds (thousands?) of people to build guitars. Those that want to rush in, dont want to draw plans, expect all measurements to be given to them, etc etc, NEVER succeed. Ive seen it happen too many times. Of course, feel free to prove me wrong!

Regards,
Perry Ormsby

Pevious builds:
HERE!
#3
I never said I didn't want to draw a plan, and I do have a book, although I couldn't make out exactly what it was telling me, so I thought that I needed some human help.

So, the scale length of 25-1/2" is just a theoretical number that doesn't actually exist on the guitar except for its use in calculating fret spacing and bridge placement? (Perhaps it's best to just start with one question =P)

Oh, and how does the scale length relate to the bridge position? That's something else I meant to ask.

Thanks for helping to clear this up for me by the way, I'd hate to even think about making a plan before I knew how to
Last edited by psyks at Feb 18, 2008,
#4
Quote by psyks
I never said I didn't want to draw a plan, and I do have a book, although I couldn't make out exactly what it was telling me, so I thought that I needed some human help.

So, the scale length of 25-1/2" is just a theoretical number that doesn't actually exist on the guitar except for its use in calculating fret spacing and bridge placement? (Perhaps it's best to just start with one question =P)


Correct

Regards,
Perry Ormsby

Pevious builds:
HERE!
#5
I've seen fret calculators online and I've read about the 18th rule, so from the scale length, I would safely be able to work out the fret placements. However I don't understand the idea of bridge placement in relation to scale length

basically, what is the theory behind bridge placement?
#6
The saddles need to be moved rearward of the scale length, to compensate for the increase in string tension when the string is fretted. Lengthening the string length (for the same scale length), lowers the pitch.

The bridge should be located so the saddles can be moved rearward of the scale length. They will not EVER need to be moved forwards (shortening) of the scale length. Adjust ALL the saddles to their forward most position. Place the bridge so they are now AT the scale length. When you do the setup, they will be moved back. The bass side of a tunomatic needs to be moved back 5mm, to allow for the lack of adjustability in this design.

Regards,
Perry Ormsby

Pevious builds:
HERE!
#7
ooohhhhhh, omg! I love these moments, in the deepest darkest depths of confusion, and suddenly being enveloped in the light of understanding... and suddenly... everything makes sense.

I'm just going to repeat what you've explained in my own words, please tell me if I have this right.

The scale length of a guitar is a theoretical number, that is used to calculate the position of all the important parts of a guitar in relation to each other. For example, 25-1/2" doesn't appear on the guitar other than in it's influence of the bridge position and fret positions.

Fretting is worked out using the 18th rule etc, or a calc on the internet

The bridge position is worked out by putting all the saddles in their forward most positions, then aligning the bridge so the all the saddles are actually at 25-1/2" from the nut. Then moving the bass side of the bridge 5 mm back and assuming that I got all of that right. marking it off and routing a cavity for both it and the tailpiece.

Then (please say I've got this right) after the guitar is finished, like with all the electronics in place, and tuners etc. Tune each string so that it's in tune, and the simple check intonation and move the saddles backwards accordingly?
#8
I think you got it... The angling of the saddle is just for that TOM you've got, but not for trems and Tele-style bridges, of course.

...I think the 18th rule is a little tiny bit inaccurate, is it not? The ratio of the distance from fret to bridge from any two adjacent frets needs to be the twelfth root of two, as far as I can recall. I can't be arsed to do that math right now, so I'm gonna look it up in my book ("Make Your Own Electric Guitar" by Melvyn Hiscock. I think you should check it out). Here it is- the '18' should be 17.817, according to Melvyn. What's your word on that, Perry?
#9
My word on it is that its sooo much easier to simply purchase a pre-slotted fretboard, it aint worth the brain strain to work out all the 18rule crap that goes with it

Of course, the tools to slot your own board are way more than the $8 or so dollars it cost to have it pre done at stewmac etc.

Regards,
Perry Ormsby

Pevious builds:
HERE!
#10
As tempting as it is to buy such a thing as a preslotted fretboard. I feel that I wouldn't learn as much if I chickened out. Plus buying the tools and learning knowledge would pay off eventually.

Thanks for your guidance, this has helped me out a lot and I feel almost ready to start making my plans