Dremel universal keyless chuck 0.4 to 3.4 mm 2615448632 (Tools & Accessories)
Imagine you want to spend a grinding disc (3.2mm) to make a hole of 1 mm, it is necessary to unscrew the head completely, change the clamp screw completely. Ben there, done! you use this chuck like a drill. I had a slight doubt about concentricity, b