On precision... Do you know the best way to gauge the alignment between two pieces of wood? This need comes up frequently in woodworking, and getting alignment wrong means (at best) a lot of sanding and (at worst) discarding a piece of work. So what's the best way to determine whether two pieces of wood are lined up exactly?
Most woodworkers already know the answer, either from a mentor early in their woodworking efforts, or through hard experience. I'm in the former camp, myself – my grandfather (father's side) taught me this simple technique.
Most non-woodworkers don't know this technique, and if asked to speculate, will usually come up with answer involving a known straight edge and squinting at how it sits across the joint that is supposed to be lined up. That technique is difficult and quite error-prone – and isn't all that accurate anyway. The best way actually involves no tools or instruments of any kind – just your finger! All you do is run your finger across the joint to feel if there's a difference in height between the two pieces of wood. Really!
A study five years ago determined that fingertips can detect surface details as small as 13 nanometers ( about 0.0000005 inches). No instrument within reach of an amateur woodworker or cabinet shop can measure anything that small.
Your fingers are a marvel of texture-detecting design – better than anything mankind has ever been able to make...