Noun phrases can be arbitrarily long in English and don't require connecting words or hyphens. This can be very confusing to people whose first language doesn't have this feature. Classic example: "Heathrow airport customer car park", a five word noun phrase (IE, noun noun noun noun noun) that native speakers find completely normal.
What's the difference between a piano and a fish?
You can tune a piano, but you can tuna fish.
You can tune a file system, but you cannot tune a fish.There's a chapter or three about planimeters, the introduction to which is the hatchet planimeter.
Worth a read if you're into geometry and Industrial Revolution stuff, and honestly, probably worth working through with pencil and paper, though I never have.
As for opportunistically relevant posting: see the first chapter of Felix Klein's Elementary Mathematics from an Advanced Standpoint: Geometry[1] for a bit on the geometric theory behind the planimeter.
[1] https://archive.org/details/elementary_mathematics_geometry/
"He shows that with two basic mechanisms, the harmonic transformer and the three-bar linkage, it is possible to perform the fundamental operations of arithmetic, addition, subtraction, multiplication and division, and to generate ballistic functions." - JOHN WOMERSLEY (https://www.nature.com/articles/162085a0.pdf)