This circle shows the notes for any given key as well as some other helpful information for major and minor scales. I created this to help me with key signatures while learning the violin after learning more about the circle of fifths and how deep it could get but I wanted something simpler I could make.

Parts just snap together. To use just spin the 1 position to your key and under you'll see the key signature (simplified to fit in small area) and you'll see helpers for the 3rd, 5th, 7th, and minor 1st.

Printed on a prusa i3 MK3S+ with a color change at just above 1 mm and in PETG Galaxy Black and Carmine Red Prusament. Using mainly 0.10mm Detail settings but with Variable layer height turned on as the joint is pretty sensitive but some heights don't need to be as defined. Likely could use PLA as well although I'd be worried about the snapping connector if it's taken apart very many times.

Print top face down to avoid bridging, using Archimedean Chords for top and bottom fill patterns, no supports should be needed.