Typical nuts, screws, bolts, and bottle caps are tightened (moved away from the observer) clockwise and loosened (moved towards the observer) counterclockwise, in accordance with the right-hand rule.
<rlpowell> my instinct is to object, but I don't think I have any actual good reasons, so: sure, that looks fine. :)<rlpowell> (that is: using "screw" to mean "rotation" seems odd to me, but I understand your arguments)