Planes are more than just a collection of parts fitted together. Clearly some planes work a whole lot better than others. Why is this? Why can one plane curl up shaving after shaving from obstinate curly maple and leave a surface with an almost polished smoothness, where another plane chatters and clogs after a few uneven planing strokes? Certainly it’s a matter of tuning and a certain harmony among the parts, a sharp iron, choosing the right plane for the work, and knowing how to use it. But it’s more than this. Some planes just have physics in their favor.

Chip Formation

The dynamics of the cut is fairly basic physics. The plane’s cutting iron contacts the wood, driving a shaving into the throat that curls and breaks against the cutting edge of the iron (and against the cap iron, too, if the plane has one). Every part…