Hi Again, you posted while I was typing.............. we need to get the terminology clear here, most important. If you mean by "the diameter of the test cut being smaller at the chuck end of the test cut bar." You mean that the lathe removed more metal nearer the chuck, or to put it another way the diameter of the test piece is smaller nearer the chuck, and gets larger as you move away from the chuck. If this is the case this would more likely be a slight twist in the bed, which can be corrected, and would mean that if you stand at the headstock end of the lathe, looking down the length of the bed, the twist is clockwise, IE the vees get slightly further away from the centre as you move away from the headstock.. Embedded chips I don't like the sound of! Is there visible scoring on the Vees, if so as long as it doesn't cover the whole of the vee, the bed should not have dropped, and you can correct wear (to a certain small amount, by slightly twisting the bed in the opposite direction, but we are getting way ahead of ourselves here) can you post up some pics of the lathe, and some closeups of the bed, especially the areas you think are the most worn.
Phil