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One of the questions I've always had. What side, high E or Low E, or even the middle.....of saddle do you use to determine placement as it relates to scale length. As an example I add 100 thou to my 24.9" scale guitars for a total length of 25 inches....and have used the middle of the saddle to determine it's location.

How bout you?

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There is no difference between the man that thinks he can....and the man that thinks he cannot.

line up the high E string to your scale length since your low E side of the saddle will be compensated depending on the width of your saddle. then square up the bridge with a triangle making sure the high E side stays at your scale length. compensation should add up to 1/2" so if you using a 1/8th saddle compensate to the low e 3/8th's of an inch when routing out your saddle groove. if its a 3/16 drop 5/16 at the low E.

P@ul,
Your numbers are way out, No guitar needs 1/2" of compensation.

There are a number of different definitions often applied to the term "scale length". For purposes of bridge location, I feel it's important to use the definition for what I refer to as "relative scale length". This is the distance from the nut to the 12th fret times 2. Though it's probably the most commonly used meaning of the term, this should not be taken for granted.

If you are adding .100" to your scale length for the saddle position (referring to the center point of the the saddle in both length and width), that's about average. I typically use .110", others may use up to .125" as a common rule. With the usual 3°-4° saddle angle pivoting around this point, any of these styles will typically leave room to fit all the intonation points within a 1/8" saddle line. This will leave you able to fit the common .040"-.060" compensation on the high E shaped to the middle-front of the saddle, and .180"-.220" on the low E shaped toward the middle-back, and fit everything in between just fine.

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Eschew obfuscation, espouse elucidation.

Agreed .. almost none (high string) to about 4-5 mm (lowest) at most for pretty much any guitar ....

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Good then....Thanks for the input. BTW it was good chatting with you the other day David. I know yer a busy fella so thanks for the information...

Thanks Tony.

Paul - When I read your reply it left me wondering. I'm finishing my 3rd guitar and when intonating...the smallest changes seemed to make a difference.

Chris

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There is no difference between the man that thinks he can....and the man that thinks he cannot.

the compensation + saddle width = the half inch. so no the compensation is not a half inch on its own your right. Thats just what i was taught and i'm new at this.

Half inch compensation length is not correct. I like to use the nut to 12th fret times 2 , then add .100 for light gauge and .125 for medium. If you are using 1/2 inch your intonation is flat. I will use these number following the line of the 1st ( hi E ) string. If I am building a higher action guitar for a flat pickin blue grasser I use a 1/8 saddle and will take the compensated length to .150
The 1/2 inch you are talking about is string height and that is not compensation length for saddle placement. I do shoot for 1/2 height at the front of the bridge and prefer a .375 bridge with .125 saddle showing.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I do what everyone else does. Staying in the center line, place a steel straight edge against the nut and make a pencil mark at the center of the 12th fret. Make a second mark about 0.12" downstream. Then move the straight edge down to the center of the 12th and put the center of your saddle slot under the second mark. Works great for me.
Terry

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Doing some research has still left me a tad confuse...

John says he follows the high E string? so the distance from the nut to the high e string is 2xscale length + compensation.

David and others say the middle of the saddle = 2x scale length + compensation.

I may be reading this wrong... but seems like there are two different answers.

I checked the Dick Boak instruction book that came with my first kit guitar hoping for a clear answer, this is what I got.

"This total combined amount is the distance from the nut to the midpoint of the saddle on the high E string" this seems to agree with Johns approach. The implied midpoint of the saddle appears to be the middle of the thickness of the saddle, not the length of the saddle...

Whatcha all think? This seems to be as critical a measurement as there is on a guitar, I guess I'm surprised at the different answers.

Make that 3 - three different definitions commonly applied to the term scale length in lutherie today. And yes, the lack of any universally accepted terminology rears it's head on occasion and can cause confusion and noteworthy complications, especially among small builders.

I won't go in to full details of who uses what definitions, as it gets quite complicated and convoluted, but this will be laid out in much more detail in an article I'm currently working on. For the time being, here's a brief summary of the three different usages, labeled and defined to my liking. I of course have ambitious hopes of seeing these definitions become more widely accepted and used within the trade, as I feel it could clarify the intentions of listed scale lengths a great deal. We'll see how that goes.....

This may seem mundane, but let's begin by defining the word scale. Here are the first two definitions you'll find in a dictionary.



Now for my proposed definitions -

Base Scale Length: The base number from which the fret spacing is calculated. In other words, it is the original length from which the fret scale (using definition #1 above) would be laid out. The usefulness of this definition is in the layout of the fret spacings themselves, though depending on by what rules you use to space your frets may not always be of use in laying out the instrument as a whole, specifically regarding things such as bridge position.

Relative Scale Length: 2× the distance from the nut to the center of the 12th fret. This is arguably a less pure definition of scale length than that of Base Scale Length, but certainly the more practical and widely used by most luthiers. This definition would not always be used in the laying out of the frets themselves, but is much more useful in the layout of the instrument after the fret positions are already determined. The use of "scale" here would better reflect definition #2 above.

Now if a fretboard were spaced according to the modern 2^(1/12) rule, and the nut were not compensated at all, the Base and Relative Scale Lengths would be in the same, and their use interchangeable in practical application. If the frets are not spaced to the 2^(1/12) rule however, or the nut position is compensated, the Base can differ significantly from the Relative. Though the Base number was used in laying out the fret slots themselves, it may now hold less influence in positioning the bridge. For bridge position it is more important to consider the Relative scale.

To complicate things further, companies like the Martin Guitar Co. have brought yet a third definition in the mix. Though it's usage is not entirely wrong, or without warrant, I still hesitate to put in bold type or recognize as a formal definition. They prefer a use of the term likely influenced or carried over from non-fretted instruments such as the violin family, but one which I feel carries notable inadequacies when applied to fretted instruments.

On instruments without frets, the scale length is the total speaking length of the string. It's use here is appropriate and necessary, as there is no rigid fret spacing by which to hold bridge placement in reference to. All compensation and intonation is of course fully flexible, and handled by the player's fingers. Contrary to fingering intervals being governed by the end string length, on fretted instruments it is the rigid, predetermined fret intervals by which the end string lengths are governed. Of course this also means that different string diameters and tensions will result in differing end lengths, assuming the frets are straight, and not curved or partitioned along their length to compensate offsets according to a constant string length.

Now that we are left with a variety of final string lengths from treble to bass, use of "scale length" in this way requires an entirely arbitrary choice of which string (and to some degree, which setup) we would like to define "scale length" by. Since there is little logical argument to be made for choosing one string over another, a universal understanding of it's meaning or intentions relies not on any reasoning or formula, but only agreement on the arbitrary reference points chosen. Since the Martin Guitar Co. has pioneered the use of this term, I choose to describe this usage as the "Martin Scale Length", and it needs to be generally understood that this describes the nut to the middle of the saddle slot at the high E string, assuming approximately .060" compensation added to the Relative Scale Length.

Simple enough, right? To be fair to Martin's use of the term, it is not entirely unlike my definition of Relative Scale Length, in that they both make use of the term scale in a similar sense as non-fretted instruments. In both cases, scale can be argued to describe the string length of an instrument relative to others (see "scale" definition 2). The distinction between these two uses, is that I feel the Martin Scale Length includes too many unnecessary variables, and relies to some degree on the whim of the person choosing the reference points. One could say it is a common and perfectly fine layman's definition of scale length, where it need not be used for critical positioning and 1/16" of an inch discrepancies are insignificant. For luthiers and technicians however, I feel the inclusion of these arbitrary compensation variables does little more than to confuse, and it is best to reserve the use of "scale length" to describe the fretboard before including any saddle compensation. On fretted instruments I prefer to describe the total string length after saddle compensation as "Open Speaking Length", or "Open String length", which of course would differ with each string, therefore rendering it less useful to consistently describe scale length.

Maybe this all seems a bit trivial and picky, but inconsistencies in use of terminology within a trade can cause very real problems in communicating effectively. I've seen more than one case where errors have been made in bridge positioning because a builder has used a fretboard slotted using one definition of the term, and the bridge located by another.

Now I just need to work on my definitions of "brief", and we'll be all set. This would be my Relatively Brief description, compared with a listing of the full details.

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Eschew obfuscation, espouse elucidation.

wow Dave! I didnt expect my brain to have to work so hard on a saturday...
So if the fingerboard was slotted by Martin (it is on the guitar I'm ready to glue up) you would use Martins formula for compensation "Martin Scale Length" (2x 12 fret + compensation as measured from the nut to the middle of the saddle at the high E string)?
What if the fingerboard was slotted by LMI? as on a guitar I am building that will be ready in about 3 weeks.

David, thanks so much for that thorough explanation! I know it took a while to write up and it is appreciated.

I want to ask one followup question just to make sure I'm not missing anything. For this question, assume there is no nut compensation so Base Scale Length would equal Relative Scale Length.

Earlier in the thread you mentioned using 0.110" compensation. Assuming an angle of 3.5 deg., the low E string will be compensated about 0.130" more than the high E string. So if you have 0.110" compensation at the middle of the saddle (lengthwise and widthwise) and use a 3.5 deg saddle angle, you have roughly 0.045" compensation for the high E string and 0.175" compensation on the low E string, correct?

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Formerly known as Adaboy.......

Judge - Martin's 25.4" scale length is actually a 25.34" scale length by the other definitions (Relative same as the Base Scale Length here, as they currently use 2/(1/12) spacing with no nut compensation). To the best of my knowledge the LMII 25.4" boards are actually a true 25.4" scale (again, relative and base the same), so the end string lengths will be approximately .060" longer than a true Martin. Same applies to the 24.9" scale I believe, as Martin short scale would be more appropriately called a 24.84". When in doubt, just measure your nut to 12th fret, use that for your relative scale length and add appropriate compensation for your bridge placement.

Darryl - It sounds like you've got the gist of it. Actual compensation at the high and low E will vary a bit. In practice, the high E will commonly end up with around .040" compensation beyond scale length. This means if you position the center of the saddle thickness at the high E at .060" beyond the relative scale, it allows the E to be ramped slightly forward, leaving sufficient room for the B string to be compensated toward the back. The low E can then be shaped toward the back of the saddle for a comfortable .200" compensation, or as much as .220" when shaped to the far back while still allowing the G-A strings enough room toward the front. Greater angles will result in the outer strings being closer to the center of the saddle and the between strings being placed closer to the edge. Lesser angles will have the opposite effect. 3° to 4° is generally the norm, and is a good range which will work just fine.

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Eschew obfuscation, espouse elucidation.

David,
Here seems to be the problem...
assume a fingerboard scale exactly 25.4", non compensated nut, angled saddle.
If I use .110" compensation as measured at the high E string, I have a string length there of 25.51". (John Hall method)

If I use .110" compensation as measured at the center of the saddle between strings 3 and 4 I would have a high E string length of approximately 25.45" (David Collins method)

Which is correct?

Maybe a better question/further research on my part, is how to calculate correct string length + compensation for each string.

Judge, I think John's .110" compensation (center slot) at the high E may have been a typo. If you were to set the saddle back that far, even on a 1/8" saddle ramped all the way to the front you would likely end up a bit flat on the high E, G, and D strings, okay with the B and low E, and the A would be a toss up.

On average, .040" at the high E and around .180"-.200" for the low (though room to move back to .220" can sometimes be of use). In the middle, maybe .080"ish for the B, .060"-.100" for the G-D, and .110"-.150" for the A. I know these are fairly broad ranges I'm giving you, but I have to admit I am just pulling them out of the ether in my head, and do not have my notes in front of me here. If you were to plan your saddle position to allow for these numbers to fit though, you should be just fine.

Keep in mind as well, that ideally these points should fall as close as reasonable to the front of the saddle to allow for a broad enough surface to bear the force of the string, but not so close on any string as to remove the option of moving the peak a tidge forward if necessary. When possible, I prefer to leave at least .015"-.020" in front of the peak on the forward most strings, to allow for a shallow roll off in front providing enough material to support the departing edge.

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Eschew obfuscation, espouse elucidation.

Thanks for your help/interest in this Dave - we had storms today and the net was out, so I am just now reading your post.

I did a bunch of research last night. .110" to at the center of the saddle at high e, seems fairly common, with bluegrass style setups.
I found this on the UMGF, from John Arnold - a man who certainly knows his stuff.

"On the first string, I locate the front edge of the saddle 2.5/32" (0.078") more than the nut to 12th distance. That is for medium gauge strings and medium action (7/64, 5/64).
Lower action or light gauge strings require a bit less compensation (2/32", usually)."
Johns .078 to the edge of the saddle would equate to somewhere around .125 at the middle of the saddle (assuming a .090" thick saddle).
I also found another thread on here that I had missed in my search earlier. John Hall, repeats his measurement here. There are some other cool ideas in here.
viewtopic.php?f=10101&t=22378&hilit=locate+bridge

I built a "saddlematic" type device today, like the stewmac jig, 12 fret to nut, then spin it and used some small allen wrenches for pins, to set the compensation.
Ive at least learned that it is important to measure each fingerboard to the 12 fret as fingerboards of the same "claimed" scale can be different.