I have a circle cutter that I inherited from my father. The directions are long gone. It's bogging down and I'm sure sharpening it would help but it's kind of unclear which is the cutting edge. Truth be told, I'm not 100% sure which way the "blade" goes in. It is square and pitched from one corner to the opposite and I'm sure that the point need to be nearer the center (otherwise it wouldn't cut clean circles) but that still leaves two possible positions.
Q1. Does the point lead or follow the other side of the blade?
Q2. How do I sharpen it? I'm thinking put it in my vice and file an edge or two but which ones?