Chambered S-type with a twist (or two)!

[ssstonelover]

I had wanted to make a "clamshell" guitar for some time. One where it chambered on the inside, but impossible to detect from the outside, a "sleeper" so to speak. This one was made from poplar 21mm thick (doubled up for thickness) and with two layers of 1/16" veneer and two layers of 0.5mm rosewood in the middle of the sandwich.
After some drawings (Illustrator) and template creation (1/4" MDF) I got down to it with the router, and then followed up with the other usual luthier tools.

Oh yeah. the things that set it apart: chambered body, active EQ, Ibanez bass type jack insert system, high access neck heel, 4x2 neck and locking tuners.

Things went pretty much to plan, however the neck I have earmarked for it turned out to be warped and with a rounded out truss rod bolt (A GFS 'factory second' I had sitting for some years and had never examined closely!). I got a Kimise 4x2 from eBay and used it, but after assembly discovered its neck scale was not a true 25.5" but 3~4mm shorter. Interesting, eh? The Wilkinson high E saddle just could not intonate, it needed to go further forward than the bridge design allowed. I substituted Graphtech saddles as the 'string break point' sits much further forward and allowed perfect intonation. Good thing I knew that. The workaround would have been to use another neck, or shave the heel of the Kimise (about 3mm) and redrill the mounting screws. Too much work for no real gain....

Specs include
-Chambered poplar body
-Graphtech saddles
-Wilkinson bridge
-4x2 locking tuners 18:1 ratio (Aliexpress)
-Artec MT3 control system and EQ
-Mystery Korean pickups
-Free-Way 10-position switch

Templates (some of them anyway)


The 2 sides of the "clam shell", initial routing 


Channel added for pickup wire runs


After adding the 'middle' veneer layers and adding another wire channel


Good view of all the 'sandwich layers'


My way of making the jack inlet.


Got to say I built it...


Neck access


Electronics, etc


Painted, buffed, built and setup.

[newey]

Beautiful work! I got all the way to the final pic before I saw that it was a lefty.

Not only is the guitar nice, the thread is a thoroughgoing layout of the build process. Gets a "like" from me just for the thread itself, every build thread should strive for this level of detail

[ssstonelover]

Thanks Newey,
The only non-lefty aspect was that I screwed up on the headstock decal and it's facing the wrong way, probably due to the fact I was using a right hand neck and had a momentary lapse of attention. Given that it's under the clear coat, I decided to live with it. Maybe it adds a human aspect, to make an error....LOL.

In terms of the design process, I spend quite a bit of time making initial 1:1 drawings to check layout as well as serve as master patterns for making the templates. Even during the build I may add features and plug those back into the drawings for future builds. For example how to make the slanted output jack hole in terms of positioning it correctly (blind hole in some respects).

[cynical1]

Very nice, as always.

I had a friend in Connecticut that was a big fan of this type of design. His favorite combination was maple on top and bottom, and about 1/4" of rosewood in between. How did you ensure the cavities all aligned properly once gluing commenced?

So, what's you take on a bass preamp in a guitar?

Again, nice guitar.

HTC1

[ssstonelover]

Alignment:
Actually I worried about alignment quite a bit from the get-go. I have a drill press and simply drilled the pickup ring screw holes down 21mm to the end of the piece and the same on the cavity screw hole on the backside. On the interior sides I had matching non-thru holes to line up too, sothe wiggle room was zero, pretty dead-on.
You then just lower one piece down on the other using long skinny drill bit to help in the guiding process.

I actually used the same principle to make the 2 templates as some features were the same on both (saving routing time) and having common holes kept the alignment as a side benefit. This might help your visualization process, though the parts are shown without the alignment screws attached or on axis.



Preamp/EQ:
The Artec MT3 is billed as being good for guitar and bass:
"Bass : +/-12 dB at 80 Hz [low E string guitar range]
"Middle : +/-12 dB at 800 Hz
"Treble : +/-12 dB at 8 kHz"

It does work and does frequency cutting as well as boosting.
The sound is very clean and low impedance I guess when at flat boost. Maybe almost a little too clean if you like more character, though we'd need Antiqua to tell us what is really going on, as that is far beyond me!
It works amazingly well with the GFS lipstick pickups (not to confuse with the mystery pickups of this guitar), almost magical. I have used it on some other guitar builds, and also the similar GFS model. It is really flexible and you can get good mid boosts when using thin single coils and super thin if you REALLY want to go the other way, so not a one trick pony, it does work. The tone pots have a center detent so it's easy enough to go back 'flat' or to boost. I have not tried it with humbuckers.
The unit also has a trim pot for gain. On this one I left it at default. If you crank it all the way and then crank the bass boost all the way, the sound gets a bit artificial/overloaded so that combination is not advised. I think the mid-gain setting I have is pretty good.

[kitwn]

What a great way to build a guitar! I'd not seen that method before but may well use it in future. Thanks for putting in so much detail.

Kit

[gckelloch]

Looks Brilliant. Must be very light. I'm getting a Black-Walnut & Roasted-Poplar Hardtail body on Monday. That or Roasted-Alder might be nice for the next version, ay?

Love those Lipsticks. I do wonder if the thin neck joint sacrifices sustain. Looks like it's down to ~1/2".

[ssstonelover]

Thanks for the kind words gckelloch

It weighs a solid lb (or even a tad more than that) less than a Strat clone I bought years ago despite having a big block steel tremolo, locking tuners and metal vs the other guitar with a thin zinc cast block, std tuners and plastic knobs. The bare body was somewhere 2.5~2.8 lbs.
Sustain seems fine, and your thickness estimate is right on, I shaved 1/4" at the joint area.

[gckelloch]

It looked like ~1/2" shaved in the pic. There should be more like 3/4" left if it was only 1/4" shaved. I'd feel more confident in that. I might leave more wood between the neck pocket and bridge, though. Less wood there and behind the bridge may reduce low-end, although the trem block cut out makes wood mass behind the bridge somewhat irrelevant. The wood in the wings doesn't really affect structural stability.

[ssstonelover]

Apr 15, 2023 10:48:49 GMT -5 gckelloch said:

It looked like ~1/2" shaved in the pic. There should be more like 3/4" left if it was only 1/4" shaved. I'd feel more confident in that. I might leave more wood between the neck pocket and bridge, though. Less wood there and behind the bridge may reduce low-end, although the trem block cut out makes wood mass behind the bridge somewhat irrelevant. The wood in the wings doesn't really affect structural stability.

To tell the truth there are many guitars with a lot less wood at the joint (than I have) doing just fine. I personally own an Ibanez SG500 34" scale base (far more string tension) that has a slimmer joint, so if it can work on a long neck bass with gobs of string tension, than there is no issue here either.
Overall it is a well-tested concept that has been on the market a long time.

The Gibson SG has the thinnest neck joint (I know of) far thinner than this one, and that one is known for some tuning instability, but that is also due to construction and material choices quite different than what I used.

[sumgai]

gc;


Also note, the direction (force vector) of the string tension is not across the neck joint (parallel to the screws), but along the joint, perpendicular to the screws. The actual amount of tension exerted across the joint is a tiny fraction of that seen along the joint. In fact, I, and I'm sure some others here, have seen totally screwless assemblies, where the neck is simply pocketed into a socket, like a tenon into a mortise. Leo simply took that concept and simplified it by removing the three of the four sides of the pocket for easy access, thus necessitating the screws for stability. But in effect, it all boils down to geometry and leverage, i.e. physics.

As Bethany points out, many similar designs have been fully realized over the years, and so far, none of them have seen a major backlash in the market. Even excepting the SG having issues due to poor material choices, there is a great number of them still in daily use across the globe, and their owners are not storming the Bastille in displeasure.  Scarf joints, on the other hand......

HTH




sumgai

[ssstonelover]

Apr 17, 2023 15:14:50 GMT -5 sumgai said:

gc;
Even excepting the SG having issues due to poor material choices, there is a great number of them still in daily use across the globe, and their owners are not storming the Bastille in displeasure.  Scarf joints, on the other hand....
sumgai

I owned an SG and had no issue and of course it is famous for a thin neck and body connection, so I don't mean to cast aspersions unnecessarily.
However it is one of the few guitars where you can do whammy bar type tone changes (mild ones) just by tugging the neck back and forth LOL. How much of that is the thin neck and how much is the connection point...I can't answer.

[gckelloch]

There was a recent video comparing the sound of an old SG and Les Paul with the same pickups. SG's do seem to have less low-end, but the newer one's are thicker. The Gibson L6-S was pretty thin, but made of Maple. The joint of a set neck is more like one piece of wood considering the sides are also glued, so the body wood on the sides contributes a lot to rigidity. I don't know of any bolt-on guitar with an entire neck heel thinner than ~7/8". I had a Basswood Ibanez RG-760 in the 90's with a neck heel that was thinner on the bottom edge for better access, but I think the top edge was at least 7/8". I actually have a cheap HB bass with an Alder body only 1.5" thick, but the neck heel is still ~7/8". 3/4" of Poplar should still be fine, as I assume is the heel thickness with this guitar. I just wouldn't feel comfortable with only 1/2" of Poplar. BTW, I got my Black-Walnut/roasted-Poplar hardtail body yesterday. The Poplar is much darker than the Walnut. It rings like a bell with a lower average freq than the Walnut. I'll post a pic in another thread.