The other day on craigslist I found a free Singer Treadle. Yesterday I went and picked it up. It is not a treadle but a Singer 99k. I am still very happy. (Who would not be for free.) My question is about the foot attachments. I did not come with any extra. I found bobbin cases on e-bay (25 for $11) but no feet. Will any Singer feet work or do I need to look for feet that will only work on 99k?