After a recent run of successful 3D prints, failure paid me a visit. I started the print and began cooking. When I came back to check, the printer had melted a huge block of plastic all around the nozzle instead of building up the desired object. The culprit was a loose bearing on the Y axis. I sorted that out and then went through the long and tedious process of tuning the bed height. Apart from a little time and filament wasted, however, no other harm was done.