I needed a master square for surface plate work, so I did what any logical person would do...grabbed a rock from the backyard, hacked it into a blank on a 10" tile saw. Then proceeded to use a combination of scraping & lapping to finish the all sides parallel & perpendicular to with in 0.0003" (three ten-thousandths).
I'm learning about the audio side of this youtube stuff, so if you can or can't hear it at a normal level, please note the time in the comments so I can address it moving forward.
