I was very pleased with this Festool C15 drill set. I substituted some deck boards, 2x6 fir, and wanted to try them on her. The first bit I used broke as soon as the countersink hit the wood. I switched to a smaller one and it broke anyway. The only time I didn't want "fast" to match its namesake! I switched to my $20 Milwaukee set, same size - no problem riding in the woods. Passed with almost no resistance. I'm pretty sure it's just a manufacturing issue, as the other reviews here are positive I'm hoping the quick quality of the metal gets drilled. Will return these, sorry folks.