HI having trouble with the threading function on a Victor 1660B Lathe. It's off .001" in 1" and when you try to go back over for the second cut it cross threads. any ideas. I did notice that the half nut when engaged lifts the lead screw a bit which doesn't seem right. i'm wondering if the upper half of the half nut is not moving down towards the lead screw and just the lower half is moving up pushing the lead screw up into the upper half and slightly flexing the lead screw which is causing the threading issue. any thoughts?