The most common position marking is the traditional dot or round Mother of Pearl (MOP) or round abalone shell.
Although there are many different patterns used in acoustic guitars, such as the snowflake, the hexagon slab and more elaborate designs, we will deal with only the traditional dots for right now.
The Common Pattern: The traditional pattern for the position markers is as follows: Single dots at the 3rd, 5th, 7th, 9th and 15th frets and a double dot at the 12th fret.
Now when I say “at the fret” I mean this is actually behind it. In other words at the 3rd fret means centered between the 2nd and 3rd fret wires.
Installing inlays is most easily done when the fretboard in sized and slotted and ready for installation. If you already have the fretboard installed on the neck, don’t worry about it we can install inlays that way as well.
Tools and Materials:
Spiral Cut Bits:
2-Part Epoxy Glue:
Garnet Sandpaper Assortment
Dremel Moto Tool 4000:
Wood Dust or Furniture Makers Black Powder:
Prepare The Inlay Holes – Method A:
Use of a Drill Press to drill inlay depressions: What I prefer to do is to use a drill bit that is slightly larger in diameter than the dot to be installed. I prefer to use a Spiral Cut Bit to drill these holes or depressions. This bit will leave a nice flat bottom so the MOP lays flat and does not tip when installed.
Measure each inlay position very precisely and use a white pencil to mark the x, y, centerline for each position dot. Now take the dot and place it on the fretboard and carefully trace around the perimeter of the dot. Do this with each dot.
Measure the thickness of the position markers you bought or made. Now set up the drill press depth stop to drill a hole about .25 mm or 1/32″ less than the thickness of the pearl. Be careful when calculating this for curved fretboards and adjust accordingly.
Using the milling bits slowly cut into the fretboard. Use a high speed setting and go extremely slow as these milling bits do not self-center, so just gradually ease it into the fretboard. Note: An alternative to the milling bit, is to use a Grinding Stone Bit. or Lapidary Stone Grinding Wheels. These will go through the wood a bit easier and they are easier to control.
Gals Tip: If this is your first time with inlay work, I would recommend that you try this process with a few dots on a scrap piece of fingerboard. It may cost you the price of the MOP, but you will not ruin a perfectly good fretboard.
Prepare The Inlay Holes – Method B:
This method utilizes the Dremel Moto Tool: Start by chucking up a down-cutting router bit into the router and then install it into a Dremel Router Base. Set the depth of the cut to just slightly less than the MOP thickness.
Carefully trace around the inlays with a sharp white artist’s pencil.
Next carefully rout out each recess with the router bit.
Glue the Inlays Into Place:
Prepare the inlay gluing mixture using slow setting 2-part Epoxy Glue. Mix the 2 parts exactly equal and then add in an equal amount of wood dust that matches the fretboard. You should save the sanding dust of fretboard for this purpose.
GLS Tip: As an alternative to the wood dust mentioned above you can purchase either Ebony Pigment or Rosewood Pigment from Stewmac. Mix with the glue for a good match for either Ebony or Rosewood.
Next fill each routed hole with the glue mixture. When the excess squeezes out, press in in with your finger as best you can. Do not worry about excess glue as that will sand off easily.
Set the fretboard aside to dry overnight.
Finishing the MOP:
Now sand the fretboard with 120 grit garnet sandpaper on a sanding block. Sand until the MOP is flush with the fretboard. Don’t forget to wear your N95 Respirator as you will be generating shell dust that is hazardous.
Now switch to 220 Garnet and the sanding block and sand until smooth.