I have a 1936 221. I have NEVER lubed the motor. I oil the machine. I got it from my grandmother around 1978. I use it constantly. She may have lubed it before I got it. Last year the machine started giving me "shock therapy". Turned out that the paper insulation had finally given out from - as the pro told me - "excess lubricant compromising the structure of the insulation." I got a new/old motor installed. After over 30 years of use - I'm thinking I'm not going to do it. Have a pro look at it every five years or so. If it needs it - they'll do it! I'm going to try to scan my manual's page about this - which says to do it every 6 months. I'll post it in Pictures if I can with the title 221 - To Lubricate the Motor