Evaluating a Neck Reset

[Brent Hutto]

If the forum will indulge a question from a rank amateur, I need some advice as to how to evaluate the condition of a classical guitar that I believe has had its neck reset. I have the instrument on approval over the weekend but unfortunately the FedEx guy came late enough that I missed my chance to take it to my normal repair-luthier.

It's a 1976 "M. Sakurai" supervised by M. Kohno and given its age the guitar is in near immaculate condition. One major fingernail-sized ding on the cedar top and a few pinpricks here and there on the rosewood back but otherwise just about new looking. The action is low (0.110" treble, 0.135" bass) with tons of saddle remaining and the strings sit 0.550" above the top at the bridge. A straightedge on the frets intersects the bridge maybe 1/16" below the top of the bridge. Basically I couldn't be more pleased with the playability and all the pertinent angles and so forth.

Here's the thing. There is a slightly jagged break in the lacquer finish where the heel cap meets the top of the body. And the last three frets on the fretboard extension curve down toward the soundhole quite noticably. There isn't a hint of a "kink" in the fingerboard where it crosses the body joint at the 12th fret. Just that little curvature down at the last couple frets. By the way this guitar supposedly has a Fleta-style dovetail joint like all Kohno guitars so if there was a neck reset it did not involve a slipper foot as best I know.

Two questions. Am I correctly reading the fretboard-extension curve and break in the lacquer at the heel cap? Isn't that a sure sign of the neck being off at some point? And assuming it has had a neck job, I'm tempting to take that as a good thing. A guitar that's 32-years-old with a cedar top would surely have high action by now otherwise, even with nylon strings (although at 659mm scale length there's plenty of tension involved). I figure someone saved me a neck reset a few years hence and now it'll be a couple decades before I need any serious work done--assuming it's a good neck reset that is.

What should I look for as signs of a half-done or problematic neck reset on this kind of guitar. I know next to nothing about classical-guitar construction and setup. Honestly, I'm so happy the guitar is otherwise immaculate that I really don't want to look too hard for trouble unless it's something important, you know?

P.S. Is it just me or could that back wood almost pass for some old, well-quartered Brazilian instead of EIR.

[Bob Webster]

I'm going to say that the guitar's neck probably was not reset. Two lines of reasoning here.

1. Nylon strings don't generate the magnitude of tension on the neck joint that would lead to inordinate changes in neck angle over time, even with a cedar top. For that reason, builders of these guitars from Torres to present time have been successful in building and maintaining perfect actions without the fallback of necks that can be reset (~99% of all classicals are built with a solid connection between the neck and the sides, top, etc.). Fleta came from a violin building background and transferred the dovetail joint practice from that experience.

2. The action numbers you provided are perfectly consistent with a building practice where the plane of the fingerboard/neck joint is aligned perfectly with the plane of the top edge of the guitar and where the fingerboard is a uniform 6mm or so in thickness. Very typical of a factory setup because there are no special tricks to make it come out that way. However, it leaves the strings very high over the top (0.550" or 14mm). Most modern builders aim for a clearance of 10-12mm over the top just to minimize torque on the bridge and its effect on the top. To achieve that, they either build in a forward set of the neck by about 2.5mm and taper the back side of the fingerboard over the body to compensate, or just taper the whole fingerboard without a forward neck set.

As for the crack in the lacquer at the heel cap, it was probably the result of a smart blow to that spot some time during its 32 year history. You didn't mention that the crack went up the sides of the neck/body joint, which would be more consistent with a neck reset or impending departure of the neck.

Then there's the curved fingerboard extension. In my estimation, it probably was a result of their practice in glueing that section during installation of the neck. That requires a clamping caul inside the body and over the fingerboard itself, clamped together to make consistent contact of the fingerboard with the body. If they clamped it with a big heavy clamp and didn't independently support the weight of the clamp, that weight will warp that section resulting in a perceivable dip. I know 'cause I've done it (once).

Overall, sounds to me like the guitar is in pretty much the shape it left the factory in, save the heel cap incident. If you like the sound of the guitar and the looks, then by all means just kick back, enjoy it, and don't worry about the structural integrity of the guitar.

Cheers,
Bob

[Brent Hutto]

Bob said:
"As for the crack in the lacquer at the heel cap, it was probably the result of a smart blow to that spot some time during its 32 year history. You didn't mention that the crack went up the sides of the neck/body joint, which would be more consistent with a neck reset or impending departure of the neck."

Thanks, Bob. In fact, examining the entire perimeter of neck-body line there is an unbroken little bead of lacquer on each side. I don't mean a big bead like caulk around your tub but a just discernible filling in of the corner with the almost clear lacquer. The only break is across the complete width of the heel cap and that break gets a little wider and more jagged toward the left edge and actually continues just 5mm or less around that corner. So that would seem totally consistent with damage to that particular spot.

Now that you induced me to find that unbroken lacquer line it occurs that my proposed neck-reset artist would have had to leave that neck-body line showing a break in the finish. This isn't French Polish or anything that can be touched up after all. I don't even think it's necessarily Nitro, I read somewhere that early on the Kohno shop was using some sort of catalyzed finish.

You've also described the neck/fingerboard arrangement perfectly. It's exactly 6mm thick over its whole length (although right at the end it may be squeezed down a tiny fraction) and now that I reexamine it with a straightedge and the bottom edge of my bifocals ;-) the curve downward almost entirely involves the last full fret (18th) and the partial fret (19th) where the fingerboard starts curving around the top of the soundhole. Funny how that little downturn at the end fools the eye into thinking the whole fingerboard extension is bent when careful use of the straightedge shows it is dead flat and in line with the rest of the fingerboard through at least the 16th. At the 17th fret it is level in the middle and on the treble side but may have a miniscule drop on the bass side.

Alright, I'm convinced. I really am enjoying the guitar. If it were a brand-new handbuilt one I'd be amazed at such a lovely setup. For one that was built during the Carter administration I just wasn't initially prepared to believe it could still be just a nice. The Kohno/Sakurai reputation for playability seems well deserved, this was their cheapest model and it's better than a lot of new instruments coming out of Spain, Mexico, China, whereever nowadays.

[Brent Hutto]

"...Very typical of a factory setup because there are no special tricks to make it come out that way. However, it leaves the strings very high over the top (0.550" or 14mm). Most modern builders aim for a clearance of 10-12mm over the top just to minimize torque on the bridge and its effect on the top..."

Thank you for this design insight. In addition to simplicity of construction and alignment, might this sometimes be a design choice as well? Especially on the bass side where my saddle is highest it would seem to me this could be a way of getting a more powerful sound, i.e. it's done at least partially on purpose. Isn't this a distant cousin to a raised fingerboard design where the action can be kept low w.r.t. the fingerboard but the strings having extra height to gain the mechanical advantage of a great angle at the saddle/bridge?

P.S. I know a decade or two later Sakurai-san started making a raised-fingerboard version of an otherwise similar guitar.