I have some old metal bobbins from an old sears machine and some from an old montgomery wards. both fit both machines. the only difference was the sears ones had a little bigger holes around the top. now my question..... I have a Janome DC2010. The only differences I see are the Janome ones are plastic and do not have the holes around the top (I do not know the purpose they served) but otherwise seem to be the same size. can the old metal ones be used if same size?