Standards
The standards behind the figures on a machine
Many figures on a printer, laser or circuit board come from documents other people wrote: a laser class, a file format, a logic level, a thread size, a filament diameter. Those documents are precise, but they cover less than a listing suggests. Each standard gets its own page in four parts — what the publishing body defines, what it leaves open, what it assumes will be used with it, and which families on this site rely on it.
Laser safety
Laser classes, the wavelength and optical density marked on protective eyewear, and what each marking defines without declaring any setup safe.
File formats
STL, 3MF, G-code and SVG: what each file carries, what it leaves out, and which machines and programs read it.
Electrical & connectors
Logic levels on hobby boards and the USB-C connector with its power negotiation, as the documents and datasheets that define them state.
Threads & fasteners
The metric thread cut on many printer nozzles and the collet system that holds cutters in desktop CNC spindles, and what each designation leaves open.
Material conventions
The filament diameter nearly every spool prints and the Shore hardness that sells flexible filament — what each convention measures and what it does not.