No matter what you say about thomasedison, it is hard to deny that he claimed to be his favorite invention: the genius of the phonograph. Capturing sound on extensible media as a physical model is a real revolution. As the main medium of recording for more than a century, the basic technology that has established several major industries is still booming.
With so much technological history, what should the aspiring inventor do when people are eager to make their own phonograph records? Use CNC router to cut easily from wood. At least this is the performance of alnwlsn after being hit by “onepercent inspiration” when cutting PCB with router. He concluded that the trace on the copper sheet might be as fine as the groove on the record, so he came up with some mathematical methods to describe a fine pitch spiral groove, superimpose the data in the sound file, and then convert the whole process into G code.
In order to find a suitable medium, he turned to the medium density fiberboard (MDF) waste board used for shipping PCB templates. After about three hours of grinding, a rather hairy 78 RPM record was generated. Surprisingly, this record was quite good when a piece of Victor was released. The spring driven motor is a bit weak for heavy wooden records and requires manual assistance, but you can more or less hear the 40 second recording clearly. More surprisingly, the recording sounded much better when the steel needle was replaced with a large toothpick. You can see the whole process in the following video. You can find the G code generation script on GitHub.
Are you confused by all this talk about reproducing music with swaying lines? Wow, OK, whippersnapper- look at [Jenny]’s primer for the MP3 generation for the background.