First Images of Fifth Prototype (patent pending)

P3241707b-600This is the TSG(tm) patent pending 5th prototype, showing:

  1. a commercial Golden Gate neck from Saga;
  2. tuners from Allparts, including locking tuners on the 4-6 strings
  3. size 9-12-17-30-43-52 steel strings
  4. a handmade Ironwood nut held in place by string pressure and copper side keepers with small screws
  5. a digitally-printed artwork soundboard/top, made of 3-ply 5mm Luaun plywood, protected by clear acrylic; attached at the neck with two washer-head wood screws, and held above the body by steel washers; attached at the tail with three small-head wood screws in the tailpiece and two washer head wood screws to the sides; aluminum foil electrostatic shielding on the back side (not showing), with retaining nuts for the bridge intonation screws
  6. a barrel-cut Marblewood bridge with aluminum spacers on an African Padauk rectangular base, with slots and locking screws and the sides for intonation adjustments
  7. two switches for future electronics to the right, with a mounting hole for a pot
  8. a tailpiece made of aluminum mini t-track track, slotted to pass the strings but not the buttons
  9. a lightweight engineered poplar body with cross-layered reinforcing at the neck and tail and t-bracing at the sides, for a total instrument weight of about 4.5 pounds (~2 kg)
  10. with moderate acoustic output, suitable for practice (not as much as a Dreadnought)

P3251716b-600This shows the mounting of the artwork soundboard at the neck (top view) with two washer-head wood screws.  The extra four holes allow for different screw mounting positions to change the resonance of the top.  From 2 to 6 screws can be used.


This shows the side view of two washers under the soundboard on the screws to float the soundboard above the body from the neck to the tailpiece, allowing for free vibrations.

P3251715b-600This shows details of the bridge and tailpiece, without the bridge base and shims.  Note that the Marblewood bridge is barrel-cut, with deeper flat grooves away from the center to allow for the neck radius.  A barrel cut seems to be more forgiving of intonation errors. The slots in the ends of the bridge allow the intonation to be set and locked.  The tailpiece is a short piece of mini-t-track from Woodcraft, of the kind used in woodworking setups.  The string slots are cut for nearly equal spacing between the sides of the strings, according to the downloadable spreadsheet on the Calculating String Spacing page.

The bridge side of the tailpiece sits even with the edge of body cross-bracing, so that the three screws holding it down and the two stainless steel side screws fix the soundboard firmly to the body along that line, allowing the string vibrations on the bridge to cause the soundboard to vibrate.


This shows the side view of the soundboard at the bridge and tailpiece, without the bridge base.  The black projections under the bridge below the soundboard are epoxied nuts for the bridge intonation screws, and do not contact the body.  Nor do the two switches.  This shows the top sandwiched firmly between the tailpiece and the cross-bracing on the body.

P3251720b-600This shows the bridge base and shims removed from the instrument.


Note that with the bridge base and shims in place, the action is too high.


But with the base removed, the action is just right.  Note how the soundboard floats above the body from the tailpiece to the neck.

P3251717b-600The image above shows the under-view of the instrument with the back/bottom plate removed.  This was never intended to be a dazzling showpiece.  It serves as a practice piece, a prototype, to determine if the dimensions and acoustics actually work.

Note that both the bottom of the soundboard and insides of the body have aluminum foil applied with spray adhesive for electrostatic shielding for future pickups.  It’s not pretty, but inexpensive and effective.

Note the under cross-bracing at the neck and tailpiece, with a cutaway a the neck for access to the neck screws, which are black washer-head wood screws.  The blobs of dark epoxy at the bridge show the brass retaining nuts for the bridge intonation lock screws peeking through.

Note the rectangular cutaway in the center of the body for mounting electromagnetic pickups, which have not yet been added, as there is no space for switching and electronics in this prototype.  Refer to the patent drawing on this page to see how that is done.

Note the side plates of 1/4-inch thick Poplar which form t-braces on the body, to add stiffness and partially form a small resonant space.

P3251718b-600Here is a side view of the same elements, showing how the sides for t-braces for the body.  The body is made of 10 different pieces of wood, each connected to the other with glue and either round or rectangular dowels.  Perhaps a bit too complicated.  Using Birch plywood would have been simpler, but using weaker soft Poplar will prove if the design holds up physically.  If it doesn’t warp under string pressure, like the first and lighter Poplar and aluminum prototype, it’s good.

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