Mandrel coming unscrewed.

[flippedcracker]

I'm planning on making the conversion to TBC, but until then, I'm stuck with what I've got. My problem is the mandrel I have is coming unscrewed from the morse taper fitting while I'm turning. I have a couple I've tried and they all do it, including the one that screws onto the headstock. I'm using a mandrel saver as I've had issues with bending mandrels, but this is a recent problem. Any ideas how to stop it?

 

[Lucky2]

Does it not have a set screw that you can tighten up on the mandrel shaft? All of mine do, but if yours doesn't you could try putting a bit of Loc-Tite on the threads. If you do use the loc-tite, make sure that you use the blue one.
Len