Due to the random thickness of box walls it is often a challenge to install a jack. Jack plates are very handy in that they work well with any wall thickness.  It is often a challenge to mount the plate squarely on the box. This new template from MGB allows you to drill mounting holes for the four jack plate screw holes.

Simply drill a 7/8 inch hole in the wall of the box, feed the jack through the opening and secure it to the plate. Then secure the plate to the box.

Place the round portion on the back of the template into the 7/8s hole and then drill the four mounting holes using a 1/16 inch or 2 mm bit.  Secure the jack to the plate then install on the box.

Click here for the Jack Plate.