I bought this product to use instead of my pneumatic straight grinder which is very productive. This rotary tool has a much better performance curve as well as much quieter operation. It worked as expected for the first 8 hours of use. Unfortunately I found a weak point, the connection between the flexible shaft and the motor. This special connection is made with a piece of aluminum that slides onto the motor shaft and is held in place with a set screw. The problem is that aluminum is a soft material. Where it connects to the flexshaft is a .038" thick crimp that allows the flexshaft to rotate in the joint once subjected to high enough stress. As a machinist, I will establish this connection. steel to solve this problem. That minor fixable issue aside, this is a great product for the price range.