+1 for Blisters idea. It works every time. that's why there is a shoulder on the mandrel and the one on the screw thread protector. Never put a morse taper center in without the thread protector for that reason :mrgreen:
If it's a bit stiff to move then keep your spanner on the shaft and use a tommy bar in the hole in the thread protector..
Also Lewis. If you get some 'dry cycle chain lubricant' from Halfords or the like and lubricate the bed bars on your lathe it makes the tool rest bango and the tail stock a lot easier to move back and forth and it won't attract the wood dust. Everything still locks OK too. I also use it on the tail stock thread, it makes winding that in and out a lot easier too :mrgreen: