I needed a screwdriver to go where none had gone before, 30 minutes later, problem solved. there are two versions, one is quite tight, which will be stronger, as the material deforms elastically around the bit, but the bit will need to be hammered in and may not be retreivable. The other is looser, but you may still need a pliers to remove the bit; it cannot be loose, since the torque would allow the bit to loosen in the holder.