Earlier this year, I finally cracked open the Helios 44-M that came with the Zenit TTL. It was horribly crusty, the glass was filthy, the aperture selector was crunchy, and the focus helicoid was pretty much stuck. Though it wasn’t strictly necessary, I decided to give it a full teardown and to thoroughly clean all its components. Nothing much seemed necessary in the way of repairs, so this seemed doable with the right tools and enough care. The one oddball tool I purchased for the job was an adjustable lens spanner. Otherwise, the standard small screwdrivers, tweezers, and needle-nose pliers did well. I re-lubricated everything, probably to higher spec than originally built.
I made a font by drawing letters in the sand and tracing their outlines. It's not a great font, but it does the job. I spent way too long making it. Feel free to download it and use it for all your papers, thank-you notes, or journal entries.