We have a machine with air pistons on it at work. It sets position by clamping on the tube. There is an insert piece that spreads the clamp pressure around the tube so it doesn't crunch. A couple times a year, they get someone new on it that takes the insert out so the screw 'can get a better grip' :mad: Within a couple days the tube is all dinged so the piston inside gets stuck and they don't understand why it won't work...:BangHead: