Originally Posted by Ramblinrev
This is absolutely completely totally wrong. The varnish needs to be cleaned off and then minimal oil used. To follow the above directions is to absolutely assure problems. Oil for sewing machines is measured in drops. And then only where the manufacturer suggests.
Not what I did in restoring close tolerance machines that had been dry, maybe for decades, following advice of those who have been restoring them for years.
I apologize if I did not make clear the difference between maintenance and restoration. On maintenance, the desired amount of oil is just what the mfg recommends and no more. In this thread, the mfg often cannot be found.
On varnish removal: Yes, such as 3-in-1 and penetrating oils can work faster and certainly better clear up linkages. But, they explicitly do not lubricate plain bearings and bushings well enough to stop wear. They can even cause it. So, they need to be flushed with oil after use. I don't know how you flush from bronze bushings except with excess.
On amount of oil. Only a drop at each point is needed for maintenance, and it would be better to be able to adjust the size of the drop, as you can with a needle applicator. For a Necchi straight stitch-only machine, I count 23 oiling points. From the original mfg booklet, in 1956, page 10: "If used continuously it should be oiled every day. For intermediate use (once or twice a week) oil it about once a week." That's not just a lot of oiling; that's a lot of oil.
If RR is concerned about attraction of lint and dust to oil: So am I. I hate grease and oil.