Peter Welsh was an historian of pre-industrial technology, a museum curator and director. This is how he introduces this paper:

This history of woodworking hand tools from the 17th to the 20th century is one of a very gradual evolution of tools through generations of craftsmen. As a result, the sources of changes in design are almost impossible to ascertain. Published sources, moreover, have been concerned primarily with the object shaped by the tool rather than the tool itself. The resulting scarcity of information is somewhat compensated for by collections in museums and restorations.

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