The problematic "Dremel" is that the speed of rotation, if it can be adapted to work such as cutting, polishing on soft materials quickly becomes incompatible with bore diameters reaching 2 mm on the same metal "soft" such as aluminum. The set of forests should should thus be limited to a maximum of 2 mm. Otherwise, forests are lz job that is expected of them: Drill! Please do not try to "over-boring" drilling the hole, breaks guaranteed!