"A clean implementation of a common lettering style found on technical drawings, engraved office signs, computer and typewriter keyboards, and some comic books

"A clean implementation of a common lettering style found on technical drawings, engraved office signs, computer and typewriter keyboards, and some comic books and avionics from the mid-20th century." Thanks to the authors/designers. I remember orange-red ink on cream paper on the circuit diagrams (schematics) glued in the lids of war-surplus electronics. Also the fold out circuit diagrams in Iliffe press books. I shall use is as the font for maths revision posters this year. I suspect that the letter forms that I remember were drawn in pen with stencils on the drawing board.