Which material is recommended for support when drilling back metal?

When drilling into back metal, using a wood block as support is often recommended because it provides several benefits. Wood is softer than metal, which means that it can absorb some of the impact and vibration generated during the drilling process. This helps to prevent the drill bit from wandering, ensuring a cleaner and more accurate hole.

Additionally, the wood can provide stability to the workpiece, reducing the risk of chipping or cracking the metal on its backside. Furthermore, a wooden block can help to prevent the workpiece from being marred by the drill bit, which is especially important when working with softer metals that might be easily damaged.

Other materials, such as plastic sheets, may not offer the same level of support and can deform under pressure, resulting in an unstable drilling surface. Metal plates, while durable, could reflect the drill bits' movements and cause the drill to slip, leading to potential inaccuracies or breakage. Ceramic bases, on the other hand, are generally too brittle for this application and can shatter if subjected to the impact of drilling.

Thus, wood blocks are favored for providing the right combination of support, stability, and protection when drilling back metal.