The jaws and the chuck body are numbered (or shud be!) 1-2-3. The back of the jaw is picked up by the scroll as you turn the key and they have to be picked up in sequence. Drop all 3 jaws into their slots, wrapping your fingers around the chuck body/jaws back the chuck key up til the #3 jaw "drops" into the scroll, no0w start the chuck to tighten and the #3 jaw should start to move down. Keeping pressure on the other jaws, continue to rotate/tighten the key and #2 jaw should follow, then #1 - and hopefully when fully closed they will then meet nicely in the middle...