Frame Grid Valve article

[Radio Fixer]

A most interesting read Joe.

Valve manufacture must have reached its pinnacle with those. The dimensions that operators could work to is amazing.

thanks Gary

[Kalee20]

Possibly - though some years ago there was interest in using nanotechnology to manufacture valves, using conical points as a cathode surface (which works by field emission rather than thermionic emission).

Grid wire diameter having a tolerance of 0.2µm is amazing...