My Othermill is great for making PCBs, metal and plastic parts at home, but with a 26k RPM spindle, it can get quite loud. In order to improve the quality of life around here while it's doing its thing, especially on long aluminum jobs, I built a sound-dampening enclosure for it. The Othermill sits in a portion of the cabinet, which is meant to hold a variety of bins for storing stock and, eventually, additional tool storage. The cabinet was cut out of a single 4' x 8' sheet of 3/4" thick plywood at UC Berkeley.
The panels I'm using for sound dampening are from McMaster-Carr, PN 5692T15. I 3D Printed orange nuts to hold them in place without having to glue them, since early tests left me a bit unsatisfied and I may switch them out in the future. In order to hold the door shut, I cut and bent two simple aluminum brackets, which hold a stretchy band between them. I used a tablesaw to cut 1/4" polycarbonate for the window, which is glued in place with hot glue.
This project is in progress and will (hopefully) be updated more soon!