Hi, new member here, loving all the great info!
I have recently acquired three vintage sewing machines;
Kenmore 158.840 (aka model 84)
Gimbels-branded Japanese zigzag
Singer 347
I bought the Kenmore and the Gimbels from a thrift store for $10 and $15 respecively. I bought the Gimbels for the cabinet, and modified it to house the Kenmore.
A few days later, I found the Singer (in cabinet) at the side of the road on garbage night. I screeched to a halt and dumped it in the back of my station wagon
Anyway, my post is about transmission fluid as a lubricant.
Transmission fluid is a light-weight mineral oil with additives.
The additives that I am interested in are the anti-oxidants, the friction modifiers and the detergents.
Regular sewing machine oil is just plain mineral oil, just like the base oil of the transmission fluid.
Regular mineral oil oxidises over time, forming a varnish-like film that gums up mechanisms.
The antioxidant additives in transmission fluid are formulated specifically to prevent this from happening.
The detergent package in ATF is designed to remove gunk and varnish from steel and keep it in solution.
The friction modifiers provide additional boundary lubrication, preventing metal-on-metal contact, ie they enhance the wear-reducing properties of the oil.
In my opinion, this makes ATF the perfect sewing machine lubricant.
I used it generously on all three of my machines.
Before application of ATF, the Kenmore moved, but was so stiff that the belt was slipping. The other two were locked up solid.
After a day or two of sitting after application of ATF, all three machines turned effortlessly and ran quietly.
Swabbing the lubricated areas with q-tips revealed that the ATF had dissolved the years of grime and had turned black as a result.
Over the next few days, I ran the machines for a few seconds, swabbed off all of the black gunk that I could reach, then reapplied ATF.
The oil now swabs off clean, and the machines run beautifully.
I believe that sewing machine oil is the cause of these frozen old machines, and will never use it on mine.
The only disadvantage of ATF is that it is red, but I was careful to wipe it away from surfaces that could come into contact with the fabric, and have not so far noticed any red marks on fabric that I have sewn.
The other alternative is Tri-Flow, but I have reservations about that.
I am concerned that the solid PTFE could accumulate over time, and could cause problems in years to come.
I have an unpleasant feeling that forums in the future will be full of posts asking how to clean old Tri-Flow off vintage machines!