I found a wonderful source for Featherweight information, supplies and notions. Nova Montgomery and she conducts FW workshops as well for maintenance. She recommends oiling every 8 hours of sewing. You can find her website here. I've copied and pasted her tips into a Word document that I printed out and put in a folder for easy reference.
http://www.novamontgomery.com/index.htm I've bought all of her laminated guide pages, the 1/4 seam guide, etc. I have no connection to her at all. I'm just a satisfied customer.