DOS

My idea was to make sure you were turning right side counter clockwise but then I got to the end of your post. I have occasionally had trouble getting BB cups to catch threads. It invariably was a matter of getting threads lined up right as the other poster noted. If cup won't catch initially, I just pull it out rotate cup a bit, re-engage, pull cup out, rotate slightly, re-engage, pull cup out, throw cup across the garage, have a beer, go to bed, come back tomorrow, rotate cup a bit, re-engage. I get there eventually.