I put side sound ports in each of my ukuleles. They send sound to the player. Here is how it is done.
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The oval shape is traced on at the proper spot and a dremel drill bit begins to cut the hole out
A sanding disk in the Dremel is used carefully to prepare the hole to receive the wooden trim ring
Very carefully the ring is fitted into the hole.
Here is what it looks like inside. The patch is to prevent a split of the side. It is maple veneer.
Once fitted, super glue is applied. when that is dried the rings trimmed flush inside and out, Job done.