Which two sizes of drill bits are commonly used for stop drilling?

In the context of stop drilling in aviation maintenance, drill bit sizes are crucial for effectively managing and repairing damage to aircraft structures. Stop drilling involves creating a hole at the end of a crack or hole to prevent it from propagating further, which can help maintain the integrity of the material.

The sizes of drill bits commonly used for stop drilling are specific to the techniques and materials involved in aircraft repair. Options like No. 30 and No. 40 drill bits are frequently utilized because they allow for precise control and help ensure that the stop drilling method is effective. These sizes provide a balance between being large enough to accommodate the necessary repair techniques while still being small enough to minimize further damage to the surrounding material.

In contrast, the other options do not reflect the standard practice in aviation maintenance for stop drilling. The sizes of drill bits listed in those options may be too large or not suitable for the goal of preventing cracks from extending, which is essential when maintaining aircraft structure integrity. Understanding the importance of selecting the correct drill bit size will assist in performing repairs that enhance safety and structural integrity during maintenance operations.