NOTE: 18 additional photos of this instrument are available. Click here for information.

        BIT LATER NOTE (6/13/05): This thing 
        is a real winner (far nicer than 
        I'd hoped). Other than my own 
        observations, several ace bass 
        players have tried it and proclaimed 
        it so. Few nights ago I got to hear 
        it played by someone other than 
        myself -- in a band situation -- me 
        on fiddle along with banjo and 
        guitar player -- & the thing IS 
        loud, and VERY nice sounding.

This article deals with a quite simple big-bodied
acoustic bass guitar I put together over the course of
about a week.

This thing is a marriage of a used, commercially made, bolt-on, 
electric bass guitar neck with an oversize body I made very 
easily and simply by "kerfing" the wood for the sides (no 
steaming etc).

More info/details/illustrations will follow as I get time to 
add it here.

I obtained this bolt-on neck for $5 at a local resale shop. 
E-bay often offers bass necks inexpensively.

The bottom & the sides are built from a four-foot long, 3/16" 
thick "handy-panel" of luan mahogany that cost about $4 at 
Home Depot.

Before we even start, let me say that the info below sounds
considerably more complicated than it actually is.


- I lightly traced the shape of my Harmony Soverign 
  guitar onto the luan, then carefully added an inch 
  to the tracing all around. To this, I added about 
  a 1/4" "overhang" to allow for slop etc. My overall 
  dimensions are:
     length of body = 21-7/8 inches
     width of body at lower bout = 18-1/4 inches
     width of body at upper bout = 14 inches
     depth (thickness) of body = 5-3/8 inches
     string length = 34-1/4 inches
     string spacing at bridge = 2-3/8 inches
     string spacing at nut = 1-5/16 inches
     overall length of instrument = 4 feet, 4 inches

- I was given an old table saw (for years, I resisted 
  getting a table saw because of it's finger-eating 
  reputation) & this saw facilitated cutting and kerfing 
  the sides. First, cut two strips of the luan, in my 
  case 5-1/2 inches by 2 feet long (I left the sides a 
  few inches long - to be trimmed off later).
- Then, to cut the kerfs, adjust the blade depth 
  experimentally until it cuts through all the plywood 
  thickness except for one layer. I made my kerfs about 3/8" 
  to 1/2" apart. Make them as parallel as possible.

- I first determined just where the INSIDE of the sides 
  should be positioned & carefully drew a line 
  representing this. Then I kerfed several lengths of 
  1/4" quarter-round molding and glued this to the inside 
  of this line, clamping with many, closely-spaced spring
  (Jumping way ahead here, I similarily glued 1/4 inch 
  quarter-round strips to the top, inside of the sides 
  -- once the sides have been attached to the bottom -- 
  where they will meet the soundboard. Spring clothespins 
  work fine as clamps here too.)

- To secure the OUTSIDE of the sides against the 1/4
  inch quarter-round molding, I simply drove
  small copper brads at about 1" interval along the outside of 
  where the sides will sit. I toke care that the sides
  wouldn't be
  pinched by the brads (allow enough clearance). These brads 
  serve as guides for the easily bendable kerfed side's bottom.
- Determine & mark (on the kerfed sides) that part of the 
  side, where the instrument's waist occurs. Even with 
  the kerfing, it seemed that this "reverse bend" would 
  break the side at the waist, so I eliminated any 
  problem here by boiling a pot of water, taking a paint 
  brush and briefly "painting" the hot water just in the 
  area where the waist is -- on the inside and the 
  outside of the wood -- be sure to soak the grooves 
  (kerfs) well. Towel off as much water as possible 
  before proceeding. This amply softens up the wood for 
  the waist bend.
- After first checking that the sides fit nicely in the 
  quarter-round/brad-wire "form", slather the side's bottom with 
  Titebond glue, align one end of a side with the center-line at 
  the small-bout end of the instrument's back, align between the 
  quarter-round molding and the brads then, using a straight plank 
  and some weight (I used rocks), let the glue dry at least 


- I made the small bout end block from a simple laminate of 
  several 1/2" thick slabs of softwood -- with the top piece 
  being a similarily dimensioned chunk of 1" thick rock 
  maple. I did this because I wanted the "bolt-on" bass neck 
  to be screwed into hardwood, but wanted the softwood 
  because of it's lightness. Glue this block in the 
  appropriate place. Once dried, coat the joint between this 
  block and the end of the side with Titebond and clamp 
  securely overnight.
- For the large bout end of the instrument, I used a 1"
  thick by 2-1/2" wide piece of rock maple. I added a small 
  angle brace for increased stability.
- The small bout end of the side now has to be carefully 
  trimmed. I did this with a t-square and multiple passes 
  with a sharp handy-knife. Make sure this cut is made 
  squarely and right at the center line. Glue the side to 
  the block like with the other block.


- Use the same "brad-form/quarter-round molding" method 
  as described above. Square up the side's end. Check 
  for fit, then repeat the above bending/hot-watering, 
  glueing and weighting. Make sure BOTH ends of the side 
  are squared up and meet the ends of the other sides 
  flush -- this was the most difficult part of my 
  instrument, but it just took time. It's FAR better to 
  ascertain this all before any glue is applies. Don't 
  worry if heigths are not exact - this can be dealt 
  with easily later. Use C-clamps for the end 
  block/side's end joint.


- I braced the back with three strips of wood, about 3/8"
  wide by a half inch tall, pointed somewhat at the top and 
  tapered down somewhat near the ends. Exact position does 
  not seem too important. I glued mine to the inside of the 
  back -- at the big bout, at the small bout and just 
  "small-bout-side" of the waist.


- No matter how carefully I tried, the side's/endblock's tops
  weren't quite the same heigth --  a simple matter of
  wrapping some sandpaper around a straight piece of wood
  and rasping away carefully (I found it helpful to use a
  stick long enough for the un-sandpapered end to rest on & ride 
  along the opposite side of the instrument. This helps keep the 
  sanding part at the proper angle).
- Similarily, the kerfed quarter-round strips had to be made 
  the same level with the sides/blocks


    NOTE: You can go a couple of different routes with the
    soundboard (in my experimenting I did both):
    a) Use a piece of the same 3/16" luan plywood (easiest)
    b) Make a spruce, cedar or (in my case) pine soundboard
       (arguably better sounding but more difficult to make)

- You only have to cut the soundhole (mine was 4-7/16 
  inches in diameter) and glue some bracing to the 
  inside of the soundboard, before gluing the whole 
  affair to the back/sides. For bracing, I chose simple 
  "brace either side of the sound-hole" & radiating 
  braces in the big bout. There are many ways to brace a 
  soundboard - just input "guitar bracing" or "+guitar 
  +bracing in Google "images" to see your options. All 
  braces were made as described above. Heavy rocks
  weighted these braces while the glue dried.
- Check everything over a few times (It's far easier to fix
  problems with the soundboard off), then apply Titebond
  atop all sides, cubes & end blocks. Weight heavily.

- A friend planed/sanded up some knot-free pine to 3/16"
  thickness. As these panels were 5-1/2" wide, I had to glue 
  four of them together to make the soundboard. This proved 
  quite easy. After first assuring that all edges were 
  straight, with minimal gaps, I just used several big, 
  stiff rubber bands around each set (2 sets of 2) of panels 
  at the same time that heavy weights were used to keep the 
  bands from "buckling" the two boards. Next step was to 
  join these two sets together. As the rubber band method 
  doesn't work with something so wide, I laid out the two 
  sets as they would be for the soundboard then elevated the 
  un-glued middle joint by laying a 3/8" high strip of wood 
  under/along the joint.I then clamped two wooden strips to 
  the worktable that just slightly "squeezed" the width of 
  the two sets. Titebond glue was applied then the 3/8" 
  strip was removed, causing the joint to drop and tighten 
  for glue drying. I applied lots of weight (heavy 
  rocks/wood planks) over the joint. Waxed paper was used on 
  both sides of the joint.


  | ! !             ! ! |
  | ! ! APPLY HEAVY ! ! | PANEL
  | ! !             ! ! |         
  | ! !WEIGHTS HERE ! ! | PANEL       

     \ \  HEAVY    / /


|_______________________ _|
  |                     |
  |  soundboard panel   | 
  |                     |  --->
 _|  soundboard panel   |______
| |_____________________|      | This stick "elevates" crack.
|_|                     |______| Remove it once glue  
  |  soundboard panel   |        is applied
  |                     |
  |  soundboard panel   |
|_________________________| Clamp these two wood pieces to
                            work table. They keep soundboard
                            strips from seperating once the 
                            "elevating stick" is removed


  | H     .    . .    H |
  | H   .   ..     .  H | 
  | H  .            . H | 
  | H                 H |
  | H                 H |
  | H  .            . H |
  | H   .   ..     .  H |
  | H     .    . .    H |

Securely glue on a 1/2" x 1/2" (or bigger) strip of wood 
("H) near both ends of the joined-together soundboard. 
These serve as temporary strengtheners - until the 
soundboard is cut out. Cut soundhole & glue on all braces 
before cutting out the soundboard's shape.


- I used an orbital, hand-belt sander & hand sanding block 
  to carefully trim away all overhangs. Use extra care here, 
  as the edge of the plywood chips very easily and ugly 
  voids might result.
This process makes a very solid and soundworthy 
instrument body. 


- Being addicted to the fretless bass, the first thing I did 
  was to rip out the neck's frets, fill in the resulting 
  grooves and smooth things out some. You could just as 
  easily keep the frets in -- bridge placement would just be 
  a bit more critical -- & on the plus side, the bass should 
  be louder with frets.
- Although this may sound crude, I very effectively mounted
  the bolt-on neck to the body by carefully drilling through
  the neck and the fingerboard at the existing screw holes, 
  enlarging the holes carefully (counter-sinking at the 
  fingerboard's surface) and screwing the neck to the 
  body with four large sheet-metal screws (carefully 
  experiment with scrap maple first to determine the best 
  pilot hole, etc). I applied a small amount of Titebond at 
  the joint for added stability. Once mounted, I covered up 
  the screw-heads with small circles of wood, cemented in 
  place with a wood-dust/Elmer's white glue mixture (for 
  easier removal if ever required. If you play up this high 
  - 22nd fret (I don't), take pains to ensure that these 
  plugs are smooth & flush.
- One benefit of this "raised fingerboard" method is that the
  bridge has to be higher, which I believe adds to the
  loudness. Also, with a higher bridge, there's more of a
  "break" as the strings ride over the bridge on their way
  to the tailpiece. By the way, I used an inexpensive 
  modified commercial guitar tailpiece.


- Mock up a trial bridge using wood scraps and popsicle
  sticks. This is a great way to determine where the bridge
  should go, how high it should be etc. Once satisfied, make
  a permanent bridge out of any hard or even softwood.
  The bridge need not be glued down -- string pressure is
  enough.  String up the animal and you're in business!
- Instruments that utilize tailpieces exert more downward 
  pressure on the soundboard than do the more commonly 
  seen bridge/pin affair. This, coupled with the fact 
  that on this bass the string height is considerably 
  higher above the soundboard than normal, means that 
  the string's pressure over the bridge might better be 
  spread out over a wider area of the soundboard. 
  Maccaferri guitars have just such a elongated bridge 
  plate. After a lot of experimentation with different 
  types & lengths of bridges, I've settled on one 11-1/2 
  inches long, 1/4 inch thick (tapered to 3/32"= inch at 
  the top) and 1-1/2 inches high in the middle (tapering 
  off to 1/8" tall at each end) to work very nicely. I 
  "swiss-cheesed" this bridge for lightness. Even with 
  this fairly large mass of maple, the thing weighs FAR
  less than say an upright bass bridge.
- I use Fender light-gauge flatwound electric bass guitar
  strings -- they play and sound great.

Illustrations, etc forthcoming

Dennis Havlena - W8MI 
Mackinac Straits, northern Michigan

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