Somebody obviously hasnt done a very good sales job on me because it's on my list of can't see the point, however I am open to persuasion. My reasoning is the sequence of events that I use to "tighten" up the mandrel nut and engage the tails stock. I put the nut on the mandrel and do not tighten it up. I then slide in the tailstock, lock it off and do not wind the tailstock in, sliding the tailstock with one finger and locking it off is quite sufficient. I then tighten the nut the minimum amount necessary to the point that I frequently have to stop the lathe and tighten it a bit more. We, the general public, see a nut or lever and think it needs to be tightenend to withstand an earthquake, not so. I have not had a problem - the live centre that I use is five years old and is not in danger of packing up yet. I may be persuaded but I have thought that things are a way of overcoming a problem which is of our own making, and that drives me to think that they are an expensive, but unnecessary remedy to a problem that shouldn't exist.