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neck angle.
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=32248		 Page 1 of 2
Author:  AquaRover [ Tue May 17, 2011 9:32 pm ]
Post subject:  neck angle.
Does anyone have suggestions for the angle of the neck in relation to the soundboard? Correct me if im wrong: the neck angle is determined by the angle of the heel block. If the glueing/screwing face of the heel block should be anything other than 90 degrees, what should it be? Thanks
Author:  Howard Klepper [ Wed May 18, 2011 1:10 am ]
Post subject:  Re: neck angle.
OP: You are apparently calling the heel of the neck the "heel block." What some call the 'heel block' is better referred to as the neck block or head block. It is inside the guitar and does not set the neck angle.

Todd: What are you calling the plane of the top, if the top has a spherical radius?
Author:  Mark Groza [ Wed May 18, 2011 8:07 am ]
Post subject:  Re: neck angle.
I start at 1.5 degrees on the neck heel to fretboard plane and adjust from there to get 1/2" string height just in front of the bridge to the top. I find very little tweeking when useing a 28' radius top.
Author:  David Newton [ Wed May 18, 2011 8:15 am ]
Post subject:  Re: neck angle.
Spherical radius top? Is there something new I don't know about?

The water-wanderer should consider, when setting his neck, not the angle of the neck to the top, but the projected line off the top of his frets, to the bridge saddle, and it's height over the top, or over the top of the bridge.

Unless... and I'm all about alternate ways of doing things even though I'm stuck in my own ways, a builder sets the "angle of the neck to the top" as his hard limit, and adjusts the height of the bridge to that, rather than adjusting the set of the neck to a "hard height bridge".

I can see doing it either way, just not by me.
Author:  Laurent Brondel [ Wed May 18, 2011 8:55 am ]
Post subject:  Re: neck angle.
AquaRover wrote:
Does anyone have suggestions for the angle of the neck in relation to the soundboard? Correct me if im wrong: the neck angle is determined by the angle of the heel block. If the glueing/screwing face of the heel block should be anything other than 90 degrees, what should it be? Thanks
The neck angle is a function of the radius used for the top, your fretboard thickness and how much you predict the top to rise under string tension (if it does). Ideally the common way of measuring that is to lay a straightedge on your fretboard and measure the space between bridge and top at the bridge location: it should ideally be between .325" and .375" (the height of your bridge). That leaves about .125" of saddle protruding from the bridge, which is a good average.
Obviously, it is clear that the angle of the heel block should be determined during construction of the soundbox, in prevision of the correct neck angle. Different ways to do things here, some like to use a flat UTB, others sand the rim at the upper bout until the proper angle is established and so on.
Personally I use a straight 90º angle, but that's because I do not use a radius per se, but a cylindrical top (flat between head and tail).
EDIT: I see Todd and I responded at the same time, roughly stating the same thing.
Author:  jfmckenna [ Wed May 18, 2011 10:17 am ]
Post subject:  Re: neck angle.
I would consider the plane of the top to be the line a straight edge makes from the center front of the bridge to the center of the head block as it lies along the top, who cares what goes on behind the bridge when determining the neck angle right? I must say I've never actually measured a neck angel on any of my guitars as I use Laurent's model as well. I simple don't work to those tolerances and each top comes out just a bit different, close but different. But if I lay a straight edge along the top and look as it runs down the edge of the fret board it's always showing a slight back angle at the nut.
Author:  David Newton [ Wed May 18, 2011 10:30 am ]
Post subject:  Re: neck angle.
Great discussion, I know we've had it before, but I forget stuff, how others do it.

I like to be able to say that i control all the things about the top of the guitar, bridge weight and thickness, top thickness, arch of, or lack thereof, the top, leaving the set of the neck to the end, all based on the size and style of guitar I'm building.

Makes me sound super, huh? Actually, everything is so loosy-goosy, this is the only way, seemingly, that works for me.
Author:  Howard Klepper [ Wed May 18, 2011 12:07 pm ]
Post subject:  Re: neck angle.
David Newton wrote:
Spherical radius top? Is there something new I don't know about?


While you were working in obscurity in Texas, a new convention has practically taken over, using those domed dishes. I don't use them myself, but I take into account when posting here that 90% of contemporary hand builders do.

I think of neck angle as something set relative to the sides at the neck joint. With my construction methods, it is around 1.25º. With a longitudinal arch to the top (like with a spherical dome) and other things equal, the angle would need to be greater than it is without that longitudinal arch. One of the things that is often not equal is how much the top comes up under string tension.
Author:  Mike Collins [ Wed May 18, 2011 12:27 pm ]
Post subject:  Re: neck angle.
Before you make a guitar there should be a "Blueprint" or
plan for the height you WANT your strings to be from the top.
If you follow through & build to this plan you'll not have to ask this question again.
A carefully laid out blueprint will show all the angles & such that you will need to work for.

10mm off of the top is the MOST I want to see for a steel!
also for a classical!
8mm for a "Flamenco"
To much twist from the strings if you go higher.
This probably does not help ya-but I live by these measurements so that
my guitars last for years & ;) sound great!
Mike
Author:  David Newton [ Wed May 18, 2011 12:41 pm ]
Post subject:  Re: neck angle.
Howard, yes, Texas obscurity, but I was making a joke of the arch.
To be honest, I have changed my historical practice of 15' and 25' radius, to 45' for the top.

Dishes? we don't need no stinkin' dishes.
Author:  two dogs [ Wed May 18, 2011 1:20 pm ]
Post subject:  Re: neck angle.
How do you avoid, or solve, the 12/14th fret hump?
Author:  AquaRover [ Wed May 18, 2011 2:13 pm ]
Post subject:  Re: neck angle.
Howard Klepper wrote:
David Newton wrote:
Spherical radius top? Is there something new I don't know about?


While you were working in obscurity in Texas, a new convention has practically taken over, using those domed dishes. I don't use them myself, but I take into account when posting here that 90% of contemporary hand builders do.

I think of neck angle as something set relative to the sides at the neck joint. With my construction methods, it is around 1.25º. With a longitudinal arch to the top (like with a spherical dome) and other things equal, the angle would need to be greater than it is without that longitudinal arch. One of the things that is often not equal is how much the top comes up under string tension.


Thanks for all the info!
Speaking of "those domed dishes," can anyone spare a little info on top and back radius? (It seems to be intimately linked with neck angle) How is it done with/without dishes, and will anything terrible happen if i were to make a truly flat, flat top guitar?
Author:  David Newton [ Wed May 18, 2011 2:23 pm ]
Post subject:  Re: neck angle.
Yes something terrible can happen, the plates can cup.
A truly flat-top guitar is ultimately built with a very slight arch.
Author:  jfmckenna [ Wed May 18, 2011 4:05 pm ]
Post subject:  Re: neck angle.
Gosh Mike C I never get that detailed with my plans. I mean, I know I want 10mm string height but I take care of that when it's time to set the neck. And yeah second the method of surfacing the fret board after the neck is bolted or glued on to get rid of the hump.
Author:  longdrive55 [ Wed May 18, 2011 4:11 pm ]
Post subject:  Re: neck angle.
David Newton wrote:
Howard, yes, Texas obscurity, but I was making a joke of the arch.
To be honest, I have changed my historical practice of 15' and 25' radius, to 45' for the top.

Dishes? we don't need no stinkin' dishes.


Hi David,

Can you explain what prompted you to move from 25' to 45' feet radius for your tops?

Also, with the flatter radius you now use for your tops, do you do anything to ensure the fretboard plane and the plane of the top match so you don't get either a 14th fret hump or need to add a shim under the fretboard?

I know some people advocate:
1) no bevel (radius) for the edge of the rim in the upper bout
2) flat UTB/no radius from the soundhole forward to the neckblock
3) sanding a reciprocal angle to the neck angle into the rim from the waste of the guitar forward to the neckblock
4) all of the above

Or do you just level the fretboard after the neck is on?

Thanks,

Erik
Author:  two dogs [ Wed May 18, 2011 5:36 pm ]
Post subject:  Re: neck angle.
Laurent Brondel wrote:
AquaRover wrote:
Personally I use a straight 90º angle, but that's because I do not use a radius per se, but a cylindrical top (flat between head and tail)


So then before setting the relief and the saddle, the last adjustment to the neck itself would be tweeking the thickness of the fingerboard?
Author:  Terence Kennedy [ Wed May 18, 2011 7:44 pm ]
Post subject:  Re: neck angle.
Lot's of good advice and great posts in this thread. There are so many factors in play when attempting to get a good neck set, level fretboard with just the right amount of drop off and proper fit to the body that it's really a pretty complex operation. It took a lot of guitars for me to evolve into what I'm doing now.

The ideal thing would be for you to find an established builder, buy them lunch and have them show you a system that works. Do that for starters, build a lot of guitars and you will slowly develop your own unique way of performing this critical operation. There are many different approaches that will give a good end result. I'm in the flat upper bout with the proper taper sanded into the rimset to match the planned neck angle camp. A double tenon bolt-on neck is really nice as you can do little tweaks at final assembly after finishing.

If you are going to error on the set it's better to be a little underset than over as you can correct that much more easily at final assembly with the fretboard on
Author:  Laurent Brondel [ Thu May 19, 2011 8:38 am ]
Post subject:  Re: neck angle.
two dogs wrote:
Laurent Brondel wrote:
Personally I use a straight 90º angle, but that's because I do not use a radius per se, but a cylindrical top (flat between head and tail)
So then before setting the relief and the saddle, the last adjustment to the neck itself would be tweeking the thickness of the fingerboard?
Not at all, fretboard thickness is constant, .270" thick (at its apex when radiused). My bridge is .300" high. Those are constant measurements common to all the guitars I build. Again I use a fairly dramatic lateral arch on the top, it is a slightly different system that does not behave exactly like a radiused plate. I do level and fret after the guitar is assembled though.
Author:  two dogs [ Thu May 19, 2011 11:58 am ]
Post subject:  Re: neck angle.
Thanks Todd and Laurent. [:Y:] The reason I asked is, I've built a number of ukuleles all with a 25' longitudinal arch and bolt on neck. The necks always came in at or very near 90 degrees, no problem. On the last two i decided to try leaving the UTB flat to glue in, which ended up raising the action. To lower the action I leaned the neck back a bit, which gave me the hump. Looking back it occurred to me that another .030 of fingerboard would have been a better solution. From here on I'll be putting the radius back on the UTB and learn to install fret wire on a finished instrument. wow7-eyes

Thanks again, Steve
Author:  ernie [ Thu May 19, 2011 1:31 pm ]
Post subject:  Re: neck angle.
thanks everyone for the detailed explanation. and the many points of view. I now understand the relationship between neckangle/heelblock/UTB/brace/bridge . It is much more complicated than it looks bliss bliss
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