This isn't a whole answer, but perhaps it will give you a start. There are two conceptual options: 1) create a "screw assembly" part with a BOM which contains the screw, a washer, a plug, a small plastic bag, and a printed label, or 2) a "screw sales kit" (if a "sales kit" is the correct name in OpenERP for a group of essentially unrelated parts that are sold together), which contains the same items. Which is correct depends on how important hierarchy is to you.

I may not be correctly understanding the purpose of a phantom in OpenERP, but in other systems a phantom is just like any other sub-assembly, except that it is completely ignored (i.e. pushed through, or seen as invisible) so far as pick lists, work orders, etc. are concerned, A phantom is created within a hierarchical BOM to better model the manufacturing process, but a phantom is never stocked, inventoried or sold. For example, if may be logistically efficient to issue all the parts at once that make up a particular parent assembly, but the assembly procedure is to assemble one or more sub-assemblies from the parts first, before completing the final assembly (and the sub-assemblies are never stocked or otherwise transacted). In this case, you may wish to create phantoms for the sub-assemblies.

Dale