We sewing machine nut-types hear a lot about sewing machines having all metal construction, steel gears, et cetera. I for one like those types of features, so when I was poking around in my latest project, a Pfaff 130, I was more than a little startled to see not one, but two gears that were not steel.
I didn't get photographs of the two offending parts but I can tell you where they are. A white colored nylon gear runs off the upper main shaft and provides the movement for the needle zig zag swing. The gear can be seen if you pull off the back cover of the machine. The second non-steel gear is on the rotary hook shaft. I don't know the technical term for the gear material but I'd call it a fiber gear. It is a brownish color. I did an online search and came up with "Linen Phenolic", which might be what it is.
The two non-steel gears are to me a drawback (albeit a small one) of the Pfaff 130. Then of course there is also the fiber timing belt that drives the lower shaft of the sewing machine. I can fully understand and appreciate that Pfaff chose those materials for the gears and timing belt because of the unique qualities of the materials but it wouldn't be my first choice in a machine that will last several lifetimes only if those parts can withstand the aging process.
Now on to the photos of the sewing machine. The Pfaff 130 is a fine machine that has a powerful 1.3 amp motor and has a large following.