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Hi guys

I've been reading Somogyi's books, and they certainly contain a lot of food for thought.

One thing that intrigued me was how his necks have a slight azimuthal angle at the body joint such that the centreline of the neck points toward the treble side of the body (he does this to give more fretboard space to the treble strings, in case you haven't read the books). Hopefully you understand what I mean or remember it from the books if you have read them.

First, I was wondering if any member here do this? does it have a noticeable benefit to playability?

Second, later in his book, Somogyi shows his bridge placement jig. As I see it, however, it appears to place the bridge relative to the centreline of the neck, which surely ignores the angle created at the neck joint. Therefore it seems a reasonable to assume that I don't understand how his jig works, and I cannot see an explanation in the text.
So basically, does anyone know how his jig actually works?
This is mostly for the sake of completeness, he has an interesting way of doing this and I'm just curious I suppose...

As always, I thank you guys for your time, this forum is an amazing resource, and it's great be able to learn from the experience of others!

Jonny.

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I can't find any information on what an azimuthal angle is, as relates to guitar making, or geometry in general. All the information I found says that it a very specific astronomical measurement, or geological measurement. Is that simply a Somogyi-ism? It seems to me that he sometimes adopts terms in technically incorrect ways, kinda like Leo Fender did with his "Tremelo" bar on his guitars, and his "vibrato" switch on his amplifiers.

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Old growth, shmold growth!

I don/t have the somogyi books. But in a past issue of GAL he talks about Physics of necks , and he had 3 seperate jigs for SS, class,FLamenco. these were long 24 in straightedges with a notch on one end to create the neck/body angle. The other edge was for locating the bridge position after the fingerboard had been glued on. I had a machinest make them for me, and they are worthwhile.But to save money , you could use 1/4in acrylic . I spoke to ervin awhile ago, and he confirmed their uses . Hope this helps

Jonny,

Having set a few necks while working in Ervin's shop, and observing the setting of several more, I don't recall any that were set off of center. We did use the straight edges described by Ernie for setting the neck/body angle.

I haven't read the books, but this could be a case of "do as I say, not as I do", which has been known to happen.

-Mark

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Do either of you have any pictures of these straightedges in use? Beth

Did Ervin call it 'azimuthal,' or is that the OP's term?

Azimuth is an angular measurement in a 360º spherical system. Like looking at the sky, which can be treated as a hemisphere.

I call that offset from centerline 'yaw,' which I believe is consistent with the Tait-Bryan convention (pilots please correct me if I have this wrong). 'Pitch' is what we commonly call 'neck angle.' And 'roll' is rarely taken into account in guitars, although it can be varied and has been by some builders (myself included, but not always by intention).

Of course, in a culture in which there are 'solid kerfings,' every curved surface is 'radiused,' and every convex curve can be simultaneously 'radiused' and 'parabolic,' who cares? Language is alive, usage is meaning, black is white, whatever.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Hi beth I don/t have photos of the st. edges in action, if you got a back issue of the GAL. there is a discusssion on neck physics and playing , in that article Ervin has several diagrams describing and illustrating how the jigs work, but he does not describe how he makes his dovetails etc, As to words , I believe that ervin was a english major in a former incarnation, which is kind of funny as I spoke to him in hungarian, his and mine mother language. Trust me , translating from hungarian to english is extremely difficult. Sometimes english words can be very confusing , especially for non native speakers.

I dont recall him using the term, it was me...

I was using spherical polars rather than pilot terminology, being a physicist rather than a pilot, it's what I'm used to. I shall adopt the convention, however, if it makes things easier (it offers a more complete description of neck at any rate).

I think, in this situation a diagram is the most appropriate

The on one attached photo i have drawn a red line, this shows the centreline of the body of the guitar, and therefore the neck of the guitar.

To give the treble strings an offset, Somogyi gives the neck a slight angle, as illustrated by the blue line in the second photo (note to scale). This slight gap is about 1/8th of an inch at the end of the body.

This will give the treble strings an offset if the bridge stays aligned with the body centreline, however, his neck attachment jig appears to register from the neck's centreline.

It's not a big deal, I simply wondered if anyone here used this trick to encourage string offset and knowing that a few people here have taken somogyi's course, they may know how his jig works.

hopefully the diagrams can express what I mean better than I can.

thanks

Jonny

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"Anything that happens, happens. Anything that in happening causes something else to happen, causes something else to happen. Anything that in happening happens again, happens again. Though not necessarily in that order." Douglas Adams

Sorry, I haven't read Somogyi's books and thought you were using one of his terms.
I don't know what the reasoning would be for that.
When I build 5 string basses, though, I align the fretboard center with the body center, and then offset the bridge towards the treble side of the center line by a small amount, to keep the EDGE of the low B string 1/8th of from the edge of the fretboard, making sure that the G string is also 1/8th of an inch from their side. I keep the front of the bridge perpendicular to the center line. If I didn't do this, the low B would look closer to the edge than the high G, and the strings would appear off-center, to the discerning eye. This is because there is a noticeable disparity in the bass string sizes, which is more noticeable than the disparity in acoustic strings due to the width of the bass strings making their sizes more noticeable.
I never considered that the effect is noticeable enough in guitars to warrant the offset, but perhaps Somogyi does? I'm speculating that perhaps he's keeping the string to edge relationship consistent per side that way. If that's the case, it seems to me that keeping the neck centered to the body and offsetting the bridge to the treble side would accomplish the same goal, and be easier to calculate.

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Old growth, shmold growth!

I usually offset the neck a bit, and center the bridge. Sorry, I should have said that before.

I don't know anything about how Ervin's jig works.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

It's really hard for me to imagine this making any kind of differance at all. I"ll be watching for an authoriative answer however.

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Jim Watts
http://jameswattsguitars.com

String spacing on the neck is just a matter of player preference. Some players don't care, others get very specific. I have found that, if people express a preference, it is to have more fret space on the treble side for bending. Sounds like Somogyi wants the bridge to be perfectly centered so he adjusts the neck to get that result.

I don't recall the jig in question but there are any number of ways to get there.

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Thats very interesting..how much of an offset do you use???? If you don't mind my asking...is this to get more room for the e,b and g strings????

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MK5acoustics.com

It's to get the high E a bit further from the edge of the board, so it won't get pulled off the edge; for example when doing a pull-off (or by sloppy technique). I like to see the neck align about 1/16" toward the treble side at the bridge location (that is, the neck centerline points that much to the treble side of the top's centerline), but I don't try to be exact about it. It has no effect on how I space the nut or the pin holes.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Older Martins were often set the opposite way...allowing more space on the bass edge. Some of them have offset necks, and some have offset bridges. For whatever reason, the offset ones seem to be more common in the 1950's.
My reasoning for doing it is because the bass string is thicker, which means it must be set in slightly to have the same visual space between the outside of the string and the edge of the fingerboard.

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John

Just curious, how many compensate for the string thickness variance by location of the nut slots? I used Brya Kimsey's method of locating the nut slots which uses a fixed distance from the edge of the fretboard to the outside of the string and adds half the distance of the string diameters to locate the centerline of the nut slot. All the slots for the inside strings are located so that the gap between the strings is consistent so the string diameters are part of the calculation.

Does this not create a similar clearance along the edge of the fretboard vs offsetting the neck? Angling the neck would be slightly different in that the fretboard edge increases on the treble side the further up the neck you go (and the clearance decreases on the bass side as you move up the neck).

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I assume there is some obvious reason why one wouldn't just increase the width, and the taper, of the fingerboard ever so slightly while maintaining the same nut width ( and the same string spacing at both nut and bridge) , instead of messing around with offsetting necks?

Traditionally the neck at the fret meeting the body has the same width as the bridge string spacing. For a 14 fret guitar with a 2 1/4" bridge string spacing, that means the neck at the 14th fret is 2 1/4" wide. That leaves ample space, even more so on a 12 fret guitar, and there is absolutely no need to compensate for the high E string. I sometimes use the 15th fret as a reference, for a slightly slimmer but still comfortable neck. What it means is that the neck's edges taper out more than the strings path, which is a good thing. Why? Because the string has less tension as one gets closer to the 12th fret (the middle of its course).
I've seen more than one guitar where the fretboard tapers absolutely parallel to the string path, and I think this is a mistake.
IMHO nothing is more annoying than a neck that is too narrow as it goes up toward the soundbox. For good players, fretting out is as easy on the low E string BTW.
One exception: if a player requests that the strings at the nut be as widely spaced as they can (with less than .100" spacing to the edge of the fretboard for the two E strings), I often slot the high E string a little further in (a few thous…) than the low E string.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

It seems to me a much simpler way of accomplishing the goal of having more space between the treble E string and the edge of the neck would be to vary the string spacing, by moving the position of the slots in the nut, for instance, and the position of the string holes in the bridge. Am I missing something here?

Joe

Joe: The width of the nut is fixed by the spacing of the pins in the bridge and the width of the fingerboard at a certain fret as explained by Laurent. This width is feel sensitive to most players.
ie some like one width nut some like another. The string spacing is also a part of this feel. This leaves very little room to move around at the nut end. Moving the holes on the bridge would be very easy to notice in comparison to the centre line of the top. Not too pleasing to look at in my mind.
That remines me of an incident I had when I showed a guitar to a non playing person.This person was a machinist and use to doing precision work and was very concerned about how his work looked to others. He looked the guitar a few minutes and was spending an extra long time looking at the bridge. He handed it back to me and said "Looks like you got the slot that holds the white thing a bit crooked".................................!!!
I had to spend a few minutes telling him about compensation in order to save any bit of respect he had for my workmanship..............True story! He still can't play the guitar.
Tom

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