Back in the late 50’s when I was getting started in ham radio, I visited the shack of another ham and saw among his gear a homemade oscilloscope. It was a very basic unit with a simple sweep circuit and with the vertical plates AC coupled to the plate of the audio amplifier tube of an old AM radio. Sine waves danced and slid across the screen as music and voice came from the speaker. It was a cool display that certainly helped to further arouse my interest in electronics. Since then I have had a career in electronics that involved spending thousands of hours in front of many different oscilloscopes but I never forgot that old home-brew scope and always thought I might build one myself.
Recently, I was searching the internet when I came across a description of a digital clock that uses a 3 inch scope tube as a readout: http://www.electronixandmore.com/project/scopeclock/index.html
This got me to thinking once again about building a scope, not as a clock or an adjunct to an entertainment radio, but as a general purpose device that could be useful around the shop.