What size hole do I need to drill in the table top for the MX395 button mic?
The MX395 requires a 1-inch hole.
Note that the barrel of the MX395 is only 7/8-inch, but the rubber grommets used for shock isolation fill up the other 1/8-inch. The precise outer diameter of the MX395 barrel is 22 mm (0.863 inches).
The maximum diameter of the plastic wing nut (used underneath the table to secure the MX395) is 2.25 inch