As an engineer, woodworker and model helicopter pilot I often hear the phrase "dialled in" to refer to a thing which has been perfectly set up.
Examples include: a table saw is dialled in when it has a perfectly square fence and a table which is perfectly aligned with the saw blade; a helicopter is dialled in when it is perfectly balanced and has the control input sensitivity "just right" for the pilot.
I was just wondering if anyone knows where the phrase "dialled in" came from? One wild guess is that it comes from the use of a dial indicator to make very small adjustments to achieve a high level of precision.
Best Answer
I'm not sure this idiom comes from a single source. Old radios had a "tuning dial" with an indicator for the frequency of the station that was "tuned in":
And "rheostats" (variable resistors) often had calibrated dials to permit them to be accurately set (and re-set back to the same point at a later time):
And similar knobs were used (and still are) on purely mechanical devices (eg, a metal lathe in a machine shop):
So, to "dial in" meant to adjust the knob (or knobs, for more complex devices) to achieve a desired setting.