Before Don Antonio Torres (1817-1892) started building guitars at the time of the café cantante, the so-called guitarras de tablao were used in Flamenco. They were made of local wood which was cheaper than the precious woods from America Latina. Not only did Torres invent the modern guitar, but he was also the first guitar maker who began to differentiate between the Flamenco and the classical guitar.
The Flamenco guitar is much lighter than the concert guitar. That is not only because it is made of cypress wood, but also, as mentioned in Lesson 1, because the walls of its back, sides and soundboard are much thinner. Even today, many guitar manufacturers still build their Flamenco guitars with less depth than the concert guitars, i.e. the sides of the Flamenco guitar are about one inch (2.5 cm) narrower than those of a concert guitar. To claim that a genuine Flamenco guitar must have clavijas (wooden tuning pegs) instead of a tuning machine or that these will even influence the sound of the guitar is complete nonsense.
Source: Flamenco Guitar Method by Graf-Martinez