as some others have said. Don't get them to line up a little boron right without hesitation. They feel like tweezers/burrs, only at the very end where the shank comes out of the collet. If you compare this design to the Dremel and Foredom collets, you can see the difference in the slots that run down the sides. These slots give the collet its spring force. Dremel and Fordome have long slots, about 3/4 the length of the collet. This gives the collet a large contact surface for the drill/mill shank. In comparison, these temo collet chucks have very short side serrations.