Neck Angle/ Bridge Relationship

[Lawrence Dell]

Hello folks

As a newcomer, it's nice to be here.  I'm a self-taught novice builder and completed my first dreadnaught this past spring.  The only components I didn't craft myself were the linings and the maple bindings (no kits).  I even made my own bending jig.  It could have been beginners luck, but somehow I was able to produce an instrument with excellent tonal quality and sustain.  But unfortunately I set the neck angle too narrow and will never achieve the low action and playability most skilled guitarists would desire without a reset, myself included.  In building this instrument I used 3 different books, 2 sets of blueprints and an untold number of articles and videos from the web, absolutely none of which give clear instruction in setting a proper neck angle.  Everyone speaks of its importance but no one seems to be able to clearly demonstrate how to go about it, or if they do, it's made out to be more complicated than it really is.  More importantly, no one addresses the simple relationship between the top of the fretboard and the bridge.  

Here is my question for any builders or setup experts who might care to respond.  Is there not a simple rule-of-thumb for aligning the top of the fretboard to a specific height at the front of the bridge? For example, if I were to place a straight edge on top of my unfretted fretboard (no relief) and extend it across the top of the soundhole to the front of the bridge, how far below or above the top of the bridge should that line ideally intersect?  I understand that bridge and fretboard heights can vary, within limits, depending on the builder and design, but it seems to me that on any steel stringed guitar, that point of intersection should be fairly consistent to maximize setup. My limited experience tells me that it should be around 1/32 to 1/16 below the top of the bridge at normal humidity?

I just finished the body of my second D with a better structural understanding and will not be making the same mistake twice.  My actual mistake was not as much in setting the neck angle as it was in properly contouring the top/front of the rim and block. 

Thank you. Hope I haven't wasted your time.

Larry 

 

[Hesh Breakstone]

Hi Larry and welcome to FRETS!

I build and repair and in our repair business one of the things that I look at right away for any acoustic guitar coming in for work is the neck angle.

That simple rule of thumb that you are seeking for me is to have a "real" straight edge when placed on an unfretted fret board with a straight neck just skim the top of the bridge when the bridge is in it's proper location.  Hats off to you too for factoring in RH because RH can make a domed top instrument rise and fall with RH changes.

If the neck is fretted I want to see the straight edge come in over the bridge by the respective fret height.

Now others may have different specs and methods and I will admit that my method produces a very slightly over set neck angle but it works well for me and sure beats an under set neck angle where the resulting string height at say the 12th is better suited for slicing hard boiled eggs...;)

There are lots of variables too such as the amount that the top will pull upward under string tension.  Regardless that straight edge coming in just skimming the top of the bridge (once the bridge is also at final height and fitted to the top) has served me very well.  I check neck angle with the straight edge between where the D and G strings are all the way to the bridge also between the D and G.  Some builders like to have the treble side of the bridge lower for better break angle on the treble strings so this has to be factored in too if you do this.

Hope this helps and congrats on your first too!

[Lawrence Dell]

Hey Hesh

Thank you.  Thank you for confirming what my instincts were telling me.  It helps tremendously, especially as I'm now starting to shape another neck/ fret board and can move ahead with added confidence.  The overall stress level this time around is dramatically lower, too.  No substitute for experience.  

[Mark A. Kane]

Something to bear in mind when calculating the neck angle is the shape of the bridge. If your bridge has a radius that somewhat approximates the radius of the neck (a la' Martin), you can take the measurement down the center of the neck. However, if your bridge is a Taylor-style (flat across the top), then you will be better off taking the measurement along the lie of the low E string.

[Lawrence Dell]

Thanks, Mark.  I used a 17" radius on the fretboard and the bridge is probably a close match.  I actually preformed my first bridge removal about a month after I "finished" the guitar, hoping to achieve a lower action.  I removed 1/16 from the top of the bridge and re-glued. Fortunately, I used hot hide glue almost exclusively, and it wasn't the first repair I made, especially during construction.  But my bridge is now 1/4" high between the D and G, and my saddle is already down to 1/8" at that location.  Do you think I could take the bridge a little lower without sacrificing sound?  Thanks again for your interest.

[Mark McLean]

Hi Larry. For a first effort you made yourself a very good looking dred. If it sounds good as well then you hit the jackpot. And don't talk of beginners luck because these things don't put themselves together with luck. You obviously managed to apply good amounts of skill and care as well.
I have only made five guitars so I consider myself still on the learning curve. Getting the neck angle right is a challenge. I have used the same principles that Hesh outlined and that should get you in the right ballpark. However, unless you keep making the same type of instrument from the same materials, you are going to find that every one is a bit different. The amount of movement in the top and the neck under string tension is hard to predict.
You didn't say whether you used a bolt on neck or a set neck. I've got to tell you that this whole process is a whole lot easier to manage if you use a bolt on technique, because you can literally take it off and adjust neck angle as many times as you want until you have got it right. I always seem to be making adjustments a few weeks after first string up a new instrument.
Good luck with your future adventures in Luthery (most of us cannot stop at one).
Mark

[Lawrence Dell]

Hey Mark, you're absolutely correct about not being able to stop, and I think that I did hit the jackpot, so-to-speak, in regard to tonal quality.  Upon first stringing, I knew that the guitar sounded very good, especially compared to my old Guild D-35, but I didn't expect the praise placed upon it by Jeffery Seitz, a violin maker acquaintance and advocate I've had here in St. Louis for many years.  With my tail between my legs, I took the guitar to Jeff's shop for a critique and was blown away by the review. He and his associate, Marc Rennard stopped work for almost an hour, passing the guitar back and forth, asking questions and using the words outstanding and exceptional to describe its sound quality.  Needless to say, I almost fainted.  Jeff said, we're always looking for instruments with what we call "the meat". This guitar not only has the meat, its got the "gristle"

I left with an emotional buzz that lasted about a week. determined to get started on my next one as soon as possible.  I'm using the same materials, traditional Sitka Spruce, mahogany and Honduran rosewood in my attempt to do it twice in a row.  With a set mahogany neck, there's no easy way to reset.

I'm curious about your fretboard above the 14th fret and how you were able to easily rework its position. in making the angle adjustments. Could you explain a little more about that?  Thanks Mark.  Sorry about my bragging, but I couldn't resist and you asked for it.  Go Cardinals!

[Mike Kolb]

Lawrence, congrats on the fine guitar building efforts but, ummm... can I rebut?  Go SF Giants :)

[Lawrence Dell]

Thank you, Mike.  Rebuts are allowed and I'll try not to hold it against you!

[Mark McLean]

Larry

You asked about the fingerboard extension.  When I first bolt on the neck and string up I leave the fingerboard extension unglued.  It might stay that way for a few weeks while I see what happens under string tension, and do any adjustments.  Once I think it is good I will glue it down to the top using the minimum amount of a pretty weak PVA glue, so that it can be undone with a bit of heat and a spatula any time it is necessary.  For my next build I intend to go with a bolt-on and bolt-down design, as used by Dana Bourgeois and Trevor Gore and others.  Then the neck is removable at any time. 

Have you thought about using a bolt-on design for your next build?  Honestly, for steel strings the majority of small shop and build-at-home luthiers are doing it this way now (e.g. check various discussions on OLF, MIMF, AGF and ANZLF).  There is a certain amount of traditionalist tut-tutting and nay saying, and a lot of uninformed pluckers and pickers who swear they can't be as good - because it isn't the way that CFM the first did it in the 19th century.  However, there is certainly no evidence that a bolted neck is acoustically inferior to a dovetail.  Have you played a Collings, Bourgeois or Goodall - are they really inferior to a Martin?  But there is no doubt that a bolted neck design makes repair and adjustment easier throughout the life of the instrument.  And every good guitar is going to need a neck reset one day. 

Cheers

Mark

PS - I know nothing of these Cardinals and Giants you mention.  Is this some sort of catholic fairy-tale? But how about them Rabbitohs?

[Lawrence Dell]

The Cardinals are actually a group of Jewish luthiers involved in a fierce 100 year old rivalry with a group of degenerate pagans from the west, formerly from the east, known as Giants. More on luthery later

[Mike Kolb]

The Cardinals are actually a group of Jewish luthiers involved in a fierce 100 year old rivalry with a group of degenerate pagans from the west, formerly from the east, known as Giants. More on luthery later

Good one!  .... (but it was even a better game!)

The Cardinals are actually a group of Jewish luthiers involved in a fierce 100 year old rivalry with a group of degenerate pagans from the west, formerly from the east, known as Giants. More on luthery later

[Lawrence Dell]

Thanks Mark, for getting back on the bolt-on specifics.  I think that it's certainly an innovative idea and absolutely makes neck repair or adjustment a breeze.  I realize, too, that I'm now building another instrument with a shelf life, but with these initial efforts, I'm trying to focus on sound, craftsmanship and gluing technique more than anything.  The basics.  I'm also keeping track of my productive work hours this time around and imagine that a bolt-on design is more labor intensive and complicated.  As I gain more confidence and skill , I'll most likely be looking more closely at that design as an option.  As luck would have it, I have a little bit of an advantage when it comes to shaping the neck.  During the 90's I made a couple of dozen osage longbows---from wedge-shaped billets with the bark still attached.  Working with mahogany, compared to osage is like working with soft clay. Even rosewood is significantly easier to work than osage.  Anyway, I digress.

Unfortunately, I haven't had the opportunity to play or hear any of the guitars you mentioned but I'm going to make an effort.  And I know what you mean about the traditionalist nay-sayers.  One of the classic books I used, and still reference, was written in the 70's by David Russell Young.  He refers to adjustable truss rods and even dovetails as the "tinker toy philosophy" of guitar building. He eventually quit building guitars and became a master violin bow maker.  Probably figured that he could make a lot more money! 

I'm not in a position to make any judgments until I've had an opportunity to hear some of these instruments, but one of the things that gives me at least some comfort in a set neck design comes from my Guild D-35.  I'm kinda giving away my age here, but I bought it new in 1973, worked on lowering the action, and added a touch of relief,  40 years later the neck is basically unchanged except for a few thousandths of an inch of relief.  Is that the result of craftsmanship, wood quality or what?  The mystery lives on.

Thanks again Mark. I'll be checking out some of these discussions you mention too.  I'm a novice in more ways than one.  Go Birds!