the 401s to freeze up - very common - dried oil in the races - the 403 and the 503 are not as complicated so do not share that problem. I use Triflow grease on gears - oil on the moving parts once they are free and clean. The singer oil has paraffin in it and sets up but not as bad as 3-in-one oil - Glenn uses clock oil - I have an old post about the differences:
http://www.quiltingboard.com/main-f1...s-t160607.html it is very easy to search and find the information you are looking for - look above on the right - there is a space for search. You just type in what you are looking for and hit enter