Use a CD or DVD as a Reflection Guide

Place an old CD or DVD label-side-down on the workpiece and use the reflective surface to visually confirm your drill bit is perfectly perpendicular before and during drilling.

How It Works

The mirrored underside of a CD or DVD acts as a reference surface. When you place the drill bit through the center hole of the CD and look at the reflection, the bit and its reflection should form one continuous straight line. If the bit appears to bend or angle at the point where it meets the CD surface, the drill is tilted and needs adjustment. This gives you real-time visual feedback from multiple viewing angles simultaneously.

Instructions

1. Mark your drilling point on the workpiece
2. Place the CD or DVD label-side-down (shiny reflective side up) on the surface, centered over your mark with the drill bit passing through the center hole
3. Position the drill bit on the mark through the center hole of the CD
4. Look at the reflection of the drill bit in the CD surface. Tilt the drill back and forth slightly until the bit and its reflection form a perfectly straight, continuous line with no bend at the surface
5. Once aligned, start drilling at low speed while maintaining alignment
6. Glance at the reflection periodically during the first few turns to confirm you are staying straight
7. Once the bit has entered the material a fraction of an inch, the hole itself guides the bit. Remove the CD and continue drilling

Tips

• Keep an old CD in your drill case or toolbox — they come in slim sleeves that protect them from scratches
• This technique works best for drilling into flat surfaces where the CD can sit flush
• The center hole of a standard CD is 15mm (about 5/8 inch) — large enough for most common drill bit sizes
• View the reflection from at least two perpendicular angles (front and side) to confirm alignment in both planes
• This method is quick to set up and surprisingly accurate for freehand drilling

Common Mistakes

• Placing the CD reflective-side-down (label up), which provides no reflection
• Only checking alignment from one viewing angle — the bit can be straight left-to-right but tilted front-to-back
• Trying to keep the CD in place while drilling at full speed, which can shatter it
• Using a scratched or opaque CD that provides a poor reflection