Step 1: What You Need
Step 2: Making the Drill Guide
I wasn't able to take pics while cutting the mirrors, but it's very easy on thin glass. Simply dip the cutter wheel in oil and then run it along a straight edge lined up on your mark. If it makes a scratchy "fingers on the chalkboard" sound, you doing great. Light pressure is all it takes to score the mirror which can then be snapped off. When breaking it, I like to support one side of the glass on my workbench top with the scoreline even with the edge of the bench. This makes it easy to break the piece by deflecting the other side downward. It is always a good idea to wear leather gloves & eye protection when cutting glass and mirror. Remember that one mirror needs to be slightly narrower to accommodate the width of the other mirror (i.e. 2 1/2" wide and 2 3/8" wide if using 1/8" mirror).
Once your glue has dried and your mirrors are cut, attach the mirrors using double stick carpet tape or an adhesive.
Step 3: Using the Double Mirror Drill Guide
The beauty of this simple guide is that you can make adjustments as you drill to keep the bit at 90° to the surface. While not as precise as a drill press, it is quite accurate when drilling pieces too big for the press. The other advantage is that the guide is out of the way of the drill allowing the use of any size bit whether large or small.
I hope this little drill guide will be useful to you. I look forward to your comments & suggestions!