This is an 18 year old left-handed Martin D35 that my client requested a side sound-port like he had seen and heard on one of my North Rim models.
This the 4th finished instrument that i've executed a sound-port install. Location was chosen for a number of reasons relating to ease of work, safety with respect to possible internal stress on the side that may cause possible fractures during work, and the fact that you'll all ways not be too far from the bridge for any internal issues relating to future pick-up installs.
Goal to cut a sizable Oval hole, I prefer oval for aesthetics, and install 1/32 or 1/16 birch-ply backing material...
The work proceeds in this manner: The guitar must be clamp firmly in place. Tape the side of instrument for a drawing palette and to protect the instrument and draw the Oval. Then with 1/16 drill bit drill many holes 1/8 in from perimeter of oval. Next I use the StewMac Dremel base with a 1/16 cutter and free-hand cut this interior oval out.
Use tape to support this piece so it doesn't get flung out.
TAKE YOUR TIME
Now prepare the backing material so it has the same hole cut in it as well, hot-glue small cauls onto this backing material. Then dry-fit this with small C-clamps (mine have little round rubber pads on them). If all is well proceed to gluing it in place. I used
Old Brown Glue for the job, this is pre-prepared hyde glue and its great stuff. I've used it for three years now. Ounce the backing is in you'll have most of the hard work done. The rest of the job is whatever your comfortable with in removing the side material along with the backing material and taking it the rest of the way to the drawn Oval. I used an 1/8 inch cutter free-hand and home-made dowel sanding rods. Get it very smooth with a round-over then add shellac to pretty it up.
Thats it you now have your own monitor speaker.
later greg
