What RPM rating should a drill motor have when countersinking in aluminum?

When countersinking in aluminum, a drill motor should ideally have a high RPM rating, typically around 3000 RPM. This higher speed is beneficial for several reasons.

First, aluminum is a relatively soft metal, which allows for effective cutting at higher speeds. Using a higher RPM facilitates quicker removal of material and improves the finish of the countersunk area, resulting in a cleaner and more precise countersink. Additionally, operating the drill motor at this RPM reduces the chances of work hardening the aluminum during the cutting process, which can occur at lower speeds.

Moreover, at lower RPMs, the cutting tool may drag rather than cut, leading to less efficient material removal and potentially damaging the drill bit or the workpiece. Therefore, a drill motor with a rating around 3000 RPM is considered optimal for achieving the best results when countersinking aluminum.