Engine turning, or jeweling, or guilloché, or a whole host of other names, is the art of polishing a pattern of circles on a piece of metal. You see it on fine watches, and you’ll see it on art-deco metal enclosures. [Ariel] decided to explore this technique and ended up getting good results with a pencil eraser and toothpaste.
The process begins with a piece of aluminum, in this case an aluminum Open Source Hardware logo. The only other required components are a number 2 pencil, some toothpaste, and any sort of rotary tool, in this case a drill press. Toothpaste is spread over the piece to be turned, and a pencil is put in the chuck. It’s just a matter of putting circles on the aluminum after that.
This is, incidentally, exactly how engine turning and jeweling are done in the real world. Yes, the tools are a bit more expensive, but you’re still looking at a somewhat soft tool scraping a fine abrasive into a piece of metal. The trick to engine turning comes in getting a consistent pattern on the piece, something that could easily be done with a CNC machine. If anyone out there feels like putting a pencil in the collet of a CNC router, we’d love to see the results.