Sometimes it may help to know what the parts are that we are describing.  If we could get a description for some of the more obscure parts, it may help with the discussion.  I know that in some cases the models are academic, but describing as such would help as well.  Any thoughts?  For example the Advanced Assemblies book has the editing Assemblies when we are adding hole wizard and mirroring parts.  I believe that it is a block for a milling maching, but I'm not sure.