Neck joint (many questions about it)

[stevez]

Hi, New member here from Cape Town (New, but not young! pushing 63)

Following Ken’s detailed and informative article about neck angle, I have been battling with a number of questions about this aspect of the guitar.
(a) The article describes how the cheeks of the neck heel but up against the (squared) sides of the soundboard. What about an alternative approach where, rather than butting up against the sides, the cheeks are seated directly against the headblock - in other words, with the side material having been removed and shaped to create a contoured recess for the neck heel? The reason I am asking this is that it would allow one to use shims to set (or correct) the neck angle without leaving a visible gap between the neck heel and the guitar body. Would this not be easier than trying to shape the neck heel to get the correct neck angle? (Clearly the measurements will have to take this change – the thickness of the sides of about 2.2mm - into account).
(b) The article discusses the alternate approach to creating the correct neck angle whereby the top edge of the rim is sanded down from the waist curve to create an angle of about 1.5 degrees to the neck heel. When one follows this approach, does it then mean that the shoulder brace under the fingerboard should no longer taper on each end to create a bulge in the middle, in order to meet the fingerboard?
(c) Following the alternate approach, would the fingerboard not be buried into the top of the guitar when one sands the top to the same level as the top of the neck? Won’t sanding away the depth of about three index cards cause an unsightly concave in the top?
(d) Is it better to sand down the top of the guitar as described above - or to accept that a gap will exist between fingerboard and guitar top- and “force” the fingerboard down by gluing it to the top (or, alternatively even holding it down with a screw/bolt? Is there then not a danger that the finger board might break as a result?)
(e) Would the alternate approach discussed in the article be better than the approach discussed in the first part of the article - i.e. where the neck heel is cut at 89 degrees, headblock angled at 91 degrees and shoulder brace shaped to raise the top to meet the fingerboard?
(f) I would also like to get luthiers’ views on using a device such as the JLD Bridge Doctor. When I think about it, such a device might inhibit the movement of the guitar’s top, resulting in a reduction of sound quality

[ken cierp]

Welcome

First -- we don't publish things in our articles that will cause bad, buried, or unsightly things to happen -- the idea of the instruction set is to lead to an accurate, attractive fit. I would submit that you may be over thinking the process or worse trying to homoginize the facts in our instructions with something you may have read else where -- not good. Your questions lead me to believe your visualizations are not correct, especially regarding how the slope gets sanded on the rim, sound board attached, final tweaking and the end results.

Yes other methods and procedures will work (trial and error) -- the KMG concept however is to have a process that is consistant and repeatable which can apply to wide range styles and sizes (like the factories) -- every KMG kit has the same slope and attachment scheme. I do not believe any one has ever gone to the internet seeking help trying to fit the neck on a KMG kit --- Sadly that is not the case with our best selling competitors. The key of course is to have correctly sized components to begin and a process that works.

It might be helpful to read the KMG instruction manual -- 1000's of guitars have been assembled using the methods and processes outlined, many are not even KMG kits.
http://www.kennethmichaelguitars.com/kitmanual.html

Some of us in the trade call that thing the "Bridge Quack" -- need I say more?

Others please chime in -- I know we have discussed the "pocketed heel" approach ala Taylor. I am currently gathering the necessary components to build a specialized CNC machine to process the neck tenon and moritse. Getting the very clean heel profile is key to an attractive fit.

[Harold in Tn]

Ken, what are the bolts screwed into in the fingerboard?

[ken cierp]

Actually that photo is for another post can't recall just now -- but anyway, those fasteners are attached to the finger-board extension so it can be secured to the sound--board. I have the system and process ready to go but still question the need since, the fret wire imparts a downward curve which in turn compresses nicely against the sound-board.