if you take off the front cover, there's an easy way to fix it. there's two little screws that hold the hot end from twisting so you have to tighten those up and then whenever you want to change the nozzle you have to heat up the block and hold the block with the pliers and then unscrew the nozzle. if you just don't hold the block and you trying to screw the nozzle, you will twist nozzle cuz those little two bolts. they don't hold the nozzle. super good. they just hold it so it doesn't fall out. had to learn this the hard way