Many of the problems with our old typewriter seem to be the result of the overly enthusiastic application of oil and lubricants and the accumulation of dust and debris over the course of close to seventy years. I am still scrubbing out the thick gooey gunk from the insides of the machine. Because of this, I am reluctant to put any oil in the newly cleaned parts.
Back to the problem at hand: the left shift lock key was working in a lackluster and intermittent manner. My hunch was that it was gunk-related: nothing a little denatured alcohol and a careful cleaning couldn’t fix.
The shift lock has a little spring that releases a metal finger that “locks” into a notch under the shift lock key.
The metal finger felt a little sticky, so I cleaned it with denatured alcohol (being careful not to get the denatured alcohol on the exterior of the typewriter as it can take off the finish) and worked it back and forth. It freed up and moved back and forth easily after a little cleaning and the shift lock key began to work consistently.
The right side shift lock has its issues. The little metal finger was completely immovable due to goo and rust. I freed it up as well with careful cleaning and soon it was swinging easily. However, the right shift lock has another significant problem: a broken spring.
I removed the spring from the key. It’s a fine, tiny thing. I will try to find a replacement at our hardware store.