Introduction: How to Build a Bluegrass-Style Five-String Banjo

About: The official instructable for Popular Mechanics magazine, reporting on the DIY world since 1902.

Whether it's jazz, rock, blues, or folk, we Americans love our music. Not the lofty kind, heard and played in quiet concert halls or recital rooms, but our music, the music played by and for the people. While the music is uniquely ours, though, most of the instruments we use were born and bred in a classical tradition. Expect one. One shaped by African slaves, adopted and refined by Civil War entertainers, accepted into the parlors of urban society and finally reborn in the hands of innovative instrumentalists and folk music interpreters - the five-string banjo.

It's a colorful history for an instrument that's no less unique. Half drum, half fretted, string instrument, the modern banjo has nearly as much polished metal on it as a '58 Buick and a bright, distinctive sound that's familiar to all. 

When it comes to building your own banjo, it's probably easier than you think. You can buy all of the parts and tools through mail-order distributors - including resonator, pot assembly, slotted finger-board and machined neck blank. 

This project was originally published in the March 2001 issue of Popular Mechanics. You can find more great projects at Popular Mechanics DIY Central.

Step 1: Supplies

For this project, you will need:
  • curly maple neck blank
  • ebony fingerboard
  • ebony peghead veneer
  • truss rod
  • pearl inlay banks
  • fingerboard binding
  • fret wire (4 ft.)
  • side dots
  • tuning pegs
  • 5th-string peg
  • 5th-string nut
  • nut blank
  • truss-rod cover
  • curly maple resonator
  • resonator binding (2 pieces)
  • bridge
  • tailpiece
  • armrest
  • strings
  • rim rod set
  • resonator hardware
  • pot kit
  • Vintage Amber dye
  • Tobacco Brown dye
  • reducer
  • retarder
  • lacquer sanding sealer
  • gloss lacquer (2 cans)

Step 2: Making the Neck, Part 1

The machined neck comes with a truss-rod slot, and the heel is shaped to fit the rim. (Consult the drawing and Supplies List for the proper identification of all terms.)

First widen the slot at the peghead to accommodate the end of the truss rod. At the heel, glue a filler strip in the slot between the end of the rod and the end of the neck.

Bevel one end of the ebony peghead veneer so that it will be square with the flat neck surface. Use two small brads in waste areas to hold the veneer in place, and glue it to the peghead.

Trace the peghead outline on the veneer. The peghead is cut with its edges perpendicular to the fingerboard plane. Hold the neck in a jig to keep the fingerboard plane parallel to the bandsaw table while supporting the back of the peghead. After sawing the shape, file the edges smooth. Then, bore the tuning peg holes.

Step 3: Making the Neck, Part 2

Position the neck over the fingerboard so the gap between the peghead veneer and the end of the board equals the thickness of the nut. Don't align the centerline of the board with the truss-rod slot, but adjust it so it's aligned with the neck centerline from the heel to the fifth fret. Then, trace the neck on the back of the fingerboard. Adjust this cutting line to accommodate the thickness of the fingerboard binding, saw to the outside of the line and smooth the edges. Glue the binding to the fingerboard with Duco cement, using masking tape to hold the binding in place. After the glue is dry, scrape the binding flush.

Tap short locating pins cut from brads into the neck's flat surface, one at each end of the neck. Allow the pins to protrude about 1/16 in. Accurately position the finger-board over the neck and press down to impress the pin locations. Then, install the truss rod, spread glue and clamp the fingerboard to the neck using the pins to position the fingerboard. Use a perfectly straight piece of 2-in.-thick stock as a caul to ensure that the fingerboard will be flat. File the neck edges and binding flush, and finish shaping the neck with files and sandpaper.

Use a drill press to bore the fifth-string peg hole. Center the hold between the fourth and fifth frets and about 1/4 in. below the binding. The finished hole must be tapered, but for now, bore a hole to match the end of the fifth-string peg. At the peghead, add a small triangular filler block with ebony veneer in the slot over the truss-rod end.

Step 4: Fingerboard Details

To cut the pearl inlays, first make a 1/2 x 2 x 6 in. saw board to support the work. Bore a 1/2 in. hold about 1 1/2 in. from an end, and make a saw kerf from the end to the hole. Then, clamp the saw board to the end of a 2 x 6 held vertically in the vise so you can adjust the height to work comfortably. 

Carefully draw your inlay designs on paper and glue them onto the pearl blanks. Hold a blank on the saw board and use a jeweler's saw and a 32 tpi blade to cut the line. Saw with slow, deliberate strokes, rotating the blank as necessary. After all the blanks have been cut, use needle files to smooth the edges. 

To cut the recesses for the inlays, first apply white tempera paint to the inlay areas. When the paint is dry, position an inlay and trace around it with a very sharp pencil. Use a Dremel tool with a router base and a 1/16-in.-dia. bit to cut the recesses.

To secure the inlay pieces, first sand ebony to create a powder. Mix a small amount of ebony powder with ordinary wood glue. Avoid adding so much that the glue thickens noticeably. Then, spread the mix in a recess and press the inlay in place so the glue squeezes out. Allow the glue to thoroughly dry and then sand the inlays flush. After the inlays, we installed side dot markers in the fingerboard binding. 

Begin installing the frets at the wide end of the neck. Cut each fret slightly longer than the slot, and then file or grind away the tang on each end to accommodate the binding on the fingerboard edges,. Check that the slot is clear of debris and use a square bar of steel and a hammer to drive the fret into the slot. With all the frets installed, file the ends flush with the neck at an angle. 

Step 5: Attaching the Neck

First, install binding around the top and bottom of the resonator. With the tone ring and flange temporarily in place on the rim, hold the neck in position, and use a drill bit to mark the end of the neck for the hanger bolts. Then, bore the hanger-bolt pilot holes. After threading the bolts into the end of the neck, temporarily join the neck to the rum with the rim rods. Place the rim into the resonator and lay out the notch in the resonator for th neck heel. Cut the notch, refine the shape with files and test fit the resonator.

Step 6: Finishing

We finished the wooden parts of our banjo by blending colors for an antiqued look. We used alcohol-based analine dyes: Tobacco Brown for the dark areas, and Vintage Amber for the light areas. Mix the powered dyes with the reducer according to the manufacturer's instructions and add a small amount of retarder to keep the dyes from drying too quickly as they're applied. 

To color the resonator back, use a cloth to wipe on a thinned coat of the lighter color. Then, add a stronger dilution, leaving the center untouched and blending the two applications. Next, add a diluted mix of the darker dye around the perimeter of the back, blending it with the lighter area. Finally, apply a regular-strength mix of the darker color around the perimeter and blend. Be sure to work quickly so the coloring blends before the dues dry. Have plenty of clean rags on-hand.

Color the resonator side similarly, creating the blend so that it darkens at the opening for the neck. When staining the neck, create dark areas at the heel and the peghead. Color the rim and the inside of the resonator with the darkest dye. Use a single-edge razor to scrape the dye from the bindings. 

Mask the fingerboard and apply a coat of aerosol spray lacquer sanding sealer. Then, apply multiple coats of gloss spray lacquer. After three or four coats, lightly sand with 300-grit paper. Repeat the process until the lacquer is finished, following the manufacturer's instructions for drying times between coats and sanding. Flatten with cured lacquer by wetsanding with 300- and 400-grit paper, and polish with automotive polishing compound followed by wax.

Step 7: Assembly

Use a file to taper the fifth-string peg hole to match the taper of the peg. Then, remove the peg's knob and use a 1/2-in/ dowel with a hole bored in the end to drive the peg in place. Use a nut driver to install the tuning pegs in the head. But a small slot in the rounded end of the fifth-string nut. Fit it in a hole bored just before the fifth fret, so it will hold the fifth string, yet let the string bear on the fret. 

Fit the tone ring and resonator flange onto the rim and attach the neck. Then add the tension ring and head. Use four bracket hooks spaced uniformly around the pot to begin drawing the parts together. Then, add the remaining hooks and slowly increase tension on the head. Keep in mind that while a loose head will produce a muddier, deeper sound, it's easy to over-tighten the head, so proceed cautiously. Install the tailpiece and the truss-rod cover plate. 

Screw the resonator brackets to the rum under the flange. Place the pot in the resonator and mark the stud locations on the inside of the resonator so they're aligned with the brackets. Then, remove the pot, bore holes in the resonator for the studs and thread them in place. Replace the pot and secure it with thumbscrews. 

Trim the nut to a snug fit in the neck. Mark string locations around 5/16 in. apart along the nut. Then use a fine saw to start the slots. Install the strings and bridge, and carefully deepen each slot to produce acceptable action without allowing the strings to buzz on the first fret. 

Rock on!