[jrmyrnsm]

Here's the description from fitness on his old thread:

I've got this 10" long, 3/4" diameter steel rod that is an accessory for one of my fitness machines. I wrapped it and taped it with fine grade sandpaper, taped off the side of the upper bout (leaving a "slot" open as a guide for where I wanted the port so it was perfectly centered) and started sanding, using the bar the long way. Because of the arc of the upper bout, it would leave a perfect, oblong port (which is what I had in mind all along....reasoning that long and narrow, top to bottom, would disperse sound to both ears more than a more round port.

I waited until I got through the wood, checking every so often to make sure I was still "straight" and hadn't gone off line, then I used an Xacto knife to get some more of the rosewood removed and started using needle files and sandpaper to get it the rest of the way.

By doing it this way, it left a perfect oval in the finish and I just used that as a place to sand and file to.