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Hi everyone. I’ve been building for about 12 years I just finished #14. Since day 1 I’ve been working around this uncertainty because I could never get a clear concise answer on this query. As a newbie I was very confused with different answers from different experts. Maybe it’s just me but I am detail oriented so I need clear parameters. I’m sure(hope) that some newbies find the ensuing answers helpful.

If you look for info about setting up the neck angle, you’ll see that the answer is “lay a straight edge on the fretboard and adjust so the end is 1/64” above the bridge” Depending on who you ask.
Ok fine but some clarification is needed.

1- Is the fretboard glued on yet or not. If it’s not glued on then there will definitely be 1/64 inch play or give so that can’t be accurate. If the fret board is glued on that would make it very difficult to floss the neck.
2- Are the frets installed. I believe not but it’s hard to find an answer on that one
3- So 1/64th above the bridge? But my bridges are lower at the front than at the back so that doesn’t work for me although I usually am able to achieve great playability. Go figure.
4- what if the bridge is thicker higher than (normal?) so what then? Perhaps the measurement should be 1/64th above the top of the bridge pin hole?
5- With this little rule is there an assumption that the bridge and or the fretboard is a certain thickness?
6- Some builders use a measurement off the guitar top instead ~ 3/16. But again what Is the assumption about bridge or fretboard thickness.

Thanks for your input builders.

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Alain
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I used to use 3/16” off the top at the bridge, but I’m starting to take that down a bit. There’s enough play in my tooling thwt measuring and cutting 1/8” gives me 3/16” That assumes a 5/16” thick fretboard and a 3/8” bridge. I’m always messing with the method (and I’m on guitar 150 now). I get it right and then something changes and I have to figure it out again. I shoot for the strings being 1/2” over the top using a 3/8” bridge and taking into account the slight rise as the bridge bellies under tension. From your discussion, it sounds like you have some guitars that work. Why not measure those and come up with a repeatable method based on that?

Thanks Bob. It’s nice to know that you’re human too. Some (most) of my guitars have great action but I spend a crazy amount of time tweaking the setup. My last guitar (Robert Johnson Gibson copy) has a 24” scale length. I was getting crazy buzz with light strings. Mediums didn’t help much. Also made new saddles and nuts too many times to count. I also filed the frets down chasing high spots so many times I was afraid of ruining them. Eventually I got it acceptable but it’s a buzz kill (NPI) when your at that stage and things don’t work out. Maybe it’s my fretting that’s the issue. Good idea about measuring the best ones and copy they’re parameters and I agree accuracy would greatly be improved with better $$$ tools. I’m replacing the cheap ones with better as they break down which is often. Buy once cry once.

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Alain
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FWIW…

I aim for 1/2” string height at the bottom of the D string from the soundboard.

My fingerboards start out at .270, with the intent of .250 after profiling, which I do after the fingerboard is glued to the neck, and the neck is glued to the guitar.

Bridges are 3/8”.

With the neck dead flat using the truss rod, a straightedge on top just kisses the top of the bridge. This is before profiling and fretting.

I think one thing might answer a few of your questions. Though it is optimum to have your strings about 1/2" above the top of the guitar, the main goal of having the straightedge be near the top of the bridge is to have the optimum amount of saddle protruding from the bridge, in order to have some allowance for future saddle trimming when the action starts to rise. So if your bridge is thicker by the bridge pins you still want the straightedge to register at the point where the saddle will be located.

That's not how I set the angle. With the truss rod set for a straight neck I want a quality straight edge to just kiss the top or ever so slightly below perhaps .010" for an unfretted.... neck. If the neck is fretted and it shouldn't be if the neck has not been attached yet... if the neck is fretted I want the hight of the frets added to what I offered for an unfretted neck where the straight edge is that height over the bridge. .050" frets I might set the angle so the straight edge is .040" over the bridge.

We don't like fretting the board off the guitar or fretting the neck off the guitar (unless it's an electric Fender style bolt on neck) and maintain that there is an opportunity to level the board expertly when the neck is ON the guitar and then fret the thing.

Anyway some of what I am reading above leads to an over set neck, not good either.

As Barry said this is for a guitar with the optimum string height at the front of the bridge being around 1/2" off the top.

Draw it out on paper it's pretty easy to see how it all interacts when you do.

Agree - take the time to draw it out full scale, any mysteries will vanish. It also makes clear the fact that the neck angle is actually set when constructing the box and can be dialled in exactly before even starting work on the neck.

There are lots of threads on this subject with search feature but I will add this, there is no absolute method. It all depends on how much movement your neck attachment system and upper bout bracing and geometry allow under initial tension and complete settling in around six-plus months.

A double tenon bolt on neck vs a bolt on with glued extension, vs glued dovetail and extension may all move differently and require a slightly different neck angle for optimal saddle height after settling in fully.

For my double tenon Bourgeois type neck attachment system and upper bout pattern I like 1/16 above the bridge unfretted. I expect a slightly higher saddle initially that will wind up shorter and optimal after the guitar reaches it’s happy spot 6-8 months later.

If you are just barely clearing the bridge fretted and no tension you could possibly have some unpleasant surprises a year later and be looking at an early neck reset.

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

^^^^ this!

So many folks advising to simply draw it on paper and all “mysteries” will become clear. Sorry, that ain’t so. You somehow need to account for rise of the nut and bridge under tension. Mr. M. Fool has given you advice that works well for many methods of construction. It’s a really good place to start.

A drawing is informative, but by itself won’t give you the guidance you’re seeking.






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You need to include those elements, (or an educated guess at them if you are working on a new design with unfamiliar behaviour) in the drawing.

Even if you don’t include them, the drawing makes it clear and easy see to what effect a rise in the soundboard of x-amount, or y-amount of neck relief would have - so you can plan accordingly and build some tolerance into your geometry.

Yes, once you’ve got the geometry dialled in for a particular design, or if you’re doing neck resets on the same makes and models of guitar over and over, rules of thumb or the projection of a (hopefully straight) straight edge works great.

But if I’m giving advice to someone who says they’re not clear on how to set neck angle, who is building via an unknown (to me) process, to an unknown (to me) design, which will therefore produce a guitar which reacts unknowably (to me) under string tension, I say:

Do the drawing, and forget formulas or rules
of thumb.

If you are somewhat confused, it’s better to draw it out and see and understand what is going on. That understanding will help you many times down the track.

In my view this is a teach-a-man-to-fish vs give-a-man-a-fish situation and it is one area where much of the published how-to-build-a-guitar material falls short.

Which is why people end up on the internet, asking for advice

I agree with Josh the drawing is still a good way to visualize what's happening and as Tim said rightly so it's not perfect there are other influencers, sometimes. Over built guitars have minimal if any top rise and most new builders are over building like it or not. If you want to get into nits that may have an impact the stiffness of the neck assembly with rod, board, ect. String tension and gauge plays a role as a variable and so too does gravity.... where the playing position is your friend if you want uber accuracy.

Or adopt a process that gets you very close and then refine with experience and taking into account what you have learned.

Based on years in a repair shop that also builds, neck geometry is not something that every builder understands... not unusual to see pro builders - and even large factory builders (looking at you, Martin Guitar) - that are operating strictly in accordance to rule of thumb, and are thus unable to accurately forecast final neck set.

I agree that a full-scale drawing is a good idea to move towards understanding the physical relationships between the neck, top geometry, and remainder of body. It is particularly interesting to draw up the neck/fretboard profile (to include the string line) and cut it free of the paper, then draw up the body with whatever version of top geometry you prefer on another sheet of paper (flat ... really 60 foot radius glued on a flat caul from neck to soundhole; 28' radius from there to tail block for Greenridge methodology).

By moving the body and neck drawings around you can see that happens with fretboard extension and top interface, string line and bridge/saddle height (goal for us was always a 350-360 thou bridge height above top and 0.150 saddle height above bridge for 500 thou total).

Understanding the relationships that generate an accurate, repeatable neck set seems like an essential piece of luthier knowledge. I've posted the Greenridge diagram with the various planes and their relationship to bridge and saddle heights... I spent the first year there getting to the point where I could use those paper neck and body layout aids and the neck relationships diagram to explain to the guys the whole neck angle thing, then the next year having each of my neck setting calculations and setups checked before trimming the heel and committing to the glue-up or bolt-up.

While I understand the math-phobics that prefer to avoid four-function calculators or those that only want a number to shoot for (i.e., ROT) neck setting, once the relationships are understood, it gets much easier to affect neck geometry early and avoiding the often-seen "Is this neck angle OK?" post when it's too late to do anything without some significant rework.

So... as I was told early in my time over in Maryland, a hobby builder of a few instruments has the luxury of avoiding the need to understand much in terms of neck geometry, but pros - whether builders or repairers - really do not have that option.

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For the times they are a changin'

- Bob Dylan

https://www.youtube.com/watch?v=FNcbA1P95KE&t=1035s
this may help you visualize the neck angle and if have a hard time seeing a machinist scale you can use drill bits as a gauge

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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've been using the method outlined in Cumpianos book for some 25 years now though I use a bit more airspace over the saddle. That method is done on a fretted board so if you do the measurements, as I do, unfretted then just do the math. 1/32in airspace is a good place to start.

More importantly though I would say is to develop a system of building that gives you that angle by the method in which you build. in other words one day I sat down and drafted it out on paper as everybody else wisely suggested and I built my open face work board (solera) so that the neck angle is built right into it . So now I almost don't even have to think about it and almost every time I get one half an inch string spacing with a saddle that is at least 1/8 inch protruding or very close. And the fretboard is dead flat from the nut to the end extension with no dramatic fall away.

Martin uses gauges not the rule of thumb they set about 280 necks a day at the Nazareth plant alone They are not doing that bad of a job I know there was a time they had an issue but they got that worked out. If only the stores that sell them took better care in storage. Guitar center is a big no no

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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

Perhaps those gauges are a bit worn, just as the bridge positioning gauges were in the early 1970's? Otherwise, why the wide variety of bridge thicknesses necessary to push product out the door (four thicknesses at last check... with a range of between .313 and about .420 for over 1/10" in variation)?

On second thought, I may be forced to agree with your assessment of no Rule of Thumb in place... that large a variation would suggest a far higher degree of variability than a good ROT might be expected to generate. I suppose we are back to worn-out gauges as the most plausible explanation?

Finally, I will argue the notion that doing a lot of something in a workmanship-of-certainty situation (aka factory production work) yields process or quality improvement. The process may speed up, but doing more of something in a factory usually just makes more stuff, rather than stuff that is better.

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For the times they are a changin'

- Bob Dylan

you are missing a big point , Martin sets up a guitar and it is placed back in the warehouse , after 2 weeks it is pulled to recheck, if good out the door , sadly most of Martin resellers do not store a guitar the way they should. So blame the source big box stores don't care

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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

Since when did the shop handling setup become responsible for establishing and maintaining neck geometry throughout the build process? It seems like the manufacturer might have some ability and interest in accomplishing that task, as by the time the guitar ships, it would seem that that particular mare has left the barn (and to further torture the metaphor, been trailered to the new owners, raised up a few colts and fillies, and is an old friend in the pasture to the other residents of the stables).

A gauge is not an algorithm, and an algorithm is what is needed unless we are willing to accept the sort of wide range of geometries coming out of the factory door. More specifically, a gauge - the physically embodied heuristic - seems inadequate for the job given the opportunity for error.

_________________
For the times they are a changin'

- Bob Dylan

I think the big box stores can only neglect RH and temp, which would have little effect on neck angle post assembly. And since we know that they’re using different height bridges at the factory, it suggests the problem stems at the factory.

I expect tracking where things go sideways to be very difficult, as the necks and bodies go through different flow charts. I would also expect that when the necks are set in the rough stage, they are set correctly, and that subtle shifts in geometry occur in the body between point A and point Z.

Even in my own shop, where I control everything, I get the occasional guitar that just doesn’t line up. Fortunately I’m not market married to a dovetail so I just sort it out and move on.

storage of guitars is critical to the geometry , I have seen many guitars that come in, once allowed to stabilize back to a good RH often the geometry falls back into place . I see a lot of guitars in my shop from all over the country. Guitar center seems to be the worst at storing guitars. Had 2 this month ,

_________________
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

That may be so, but does not explain why they have to resort to different bridge heights at the factory. That they do so indicates a neck angle problem at the factory…

its called a tolerance all production plants do this Martins tolerance is a lot closer now than it was 10 years ago.
In the 70's they were all over the place. With cnc and statistical controls they tightened this up a great deal. They started
putting the neck angle into the side about 6 years ago. This helped a lot. I see the same on Gibson and Taylor. They rejigged the production floor and have now set up the critical steps with new jigs that are better then the old ones.
Individual builders can afford the time after all Martin , Taylor , Gibson Godin and all are production facilities so its about the numbers. I agree that the companies don't make decisions based on tone but mostly on warranty work

_________________
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