Adding the mounting nut

Tripods use a 1/4" x 20 thread to screw into the camera.

Using the 1/2" drill again, make a hole to accept a 1/4" x 20 nut.

Do your best to drill a straight hole and don't drill any deeper than needed to position the nut flush with the wood.

If you drill too deeply, just sand the wood until the nut is flush.

Done