[GH85Carrera]

Machining a Space Shuttle Main Engine injector, 1977.
A workman reams holes to the proper size and alignment in the Space Shuttle Main Engine’s main injector body, through which propellants will pass through on their way into the engine’s combustion chamber. Each of those injector nozzles is a separate piece; what we see in the picture is the whole assembly, with each of the nozzles poking through the “primary plate”. In all likelihood the injectors are prefabricated with a slightly undersized hole, pressed into the plate and reamed out to final size in this setup.