How to Locate the Center of a Hole With an Edge Finder

[Dr Stan]

I've used this technique multiple times on larger (2+") holes with good success.  On smaller holes I prefer to use a plug/pin in the spindle that fits the hole or use a small center shaped like a bull center.  Depending on the accuracy required I'll sweep the hole with an indicator to get closer after using a center finder or a pin/plug.