Neck alignment - - - measurement at bridge position

[peter havriluk]

I am doing final assembly on a kit guitar (most emphatically not anything like what Ken sells). The neck is bolted to the body in a trial fit, and a straightedge laid on the neck (no fretboard) measures 1/4" above the soundboard at the bridge position. Near as I can tell, the soundboard does not have any dome, it looks to be flat. The soundboard was braced by the kit manufacturer, so I'm not guilty of any fabrication adventures on the soundboard. The only neck block alignment, according to the assembly manual, was that the assembler be sure to achieve full contact between the neck block/fretboard support and the soundboard when assembling the soundboard to the body, and that required some jacking so as to achieve this contact.

So...

Is this 1/4" dimension within 'normal' range for installations? Long story on the kit, but I'm trying to wind up with a usable guitar I can put a finish on and travel with without worry.

For that matter, can anyone suggest what 'normal' dimensions of the height of a straightedge over the soundboard, laid on the neck, wants to be at the saddle position?

If this 1/4" gap is beyond range, can the bridge be shimmed to elevate the bridge?

Thanks, folks.

[John Parchem]

Do I understand correctly the neck is in plane with the body now? Measuring at the saddle position without a fret board is 1/4". !/4" is too high. You need to be closer to a 3/32". Sorry about my use of metric, but by the time you have a typical action the strings would 19-20 mm over the sound board. 14 mm is a better target.

I like to put a straight edge on the top starting at the top of the guitar and measuring at the saddle location. I like to see 1/16". Now if the neck angle is such that the neck is in plane with the top everything is good. So if I understood what you described correctly your sides were angled back at too steep of angle so that when the top was glued on it took that angle.

There are taller bridge. I would wait for other to chine in but I think that would be too tall. You would be over driving the top. I think in the same situation I would correct the neck angle and then work out a way to get the fret board extension to lay flat on the top. I have done it two ways:

Shaped the back side of the fret board extension so that it lays flat.

I have also corrected the angle pushed in the neck to the point that the fret board hits the top, probably near the sound hole. I would make a wedge to fit in the gap I created and adjust the holes in the block if necessary so I could bolt the neck in that location.

If you can post pictures it would help to see what is going on.

[peter havriluk]

Thanks, John. I'll try to get some pictures that show the dimensions I'm referring to. I can experiment with shims on the neck heel to see how much displacement is needed to get the air gap of a straightedge sitting on the neck at the bridge position down to 1/16" or so. Geometry being what it is, I suspect it won't be much. The neck design is a knockoff of Taylor's NT neck, so there's a very study tongue under the fretboard. I suspected I was in for some adventures. I thought the kit left too much to chance. I had no great hopes for it save as an experience builder, and as long as I can get it playable in a reasonable amount of time, it's a victory.

And did I understand correctly that what I'm looking for at the saddle location from a straightedge sitting on the neck is an air gap of about 1/16" above the soundboard?

Much obliged.

[John Parchem]

...

And did I understand correctly that what I'm looking for at the saddle location from a straightedge sitting on the neck is an air gap of about 1/16" above the soundboard?

Much obliged.

Actually I look for 2.5 mm so it is closer to 3/32". I am OK with a 16th, start to get nervous around an 1/8". Sorry I mostly work in metric.

[Tim Benware]

I too, shoot for 2/32 to 3/32 above the top (to me 3/32 is preferable).

[peter havriluk]

Thanks, folks. I'll have a happy evening tonight exploring what I'm going to do to resolve this little surprise. What is supplied as an 'instruction manual' hardly goes near this topic, so what happens next is ad hoc and based on background skills (limited, in my case) and advice (in good supply).

I'll keep in touch.