Very well esplained. Thanks to the one who wrote the text . I know a bit about harpsichord but I learned a little more here . ( Why are jacks made of pear trees.)
Hi Nicolas - that is a great question. It all has to do with the grain of the wood. The grain on pearwood is very even and it doesn't have any interlocking grain. This means it is easier to plane as your edge will slide over wood without having as much resistance from fibres growing in different directions. The wood is also very hard and stable. Almost all of these parts were made by hand, so once a particular type of material was found that would save time and effort but last, makers tended to keep using that material.
