Steel strings first became widely available in around 1900. Steel strings offered the promise of much louder guitars, but the increased tension was too much for the Torres-style fan-braced top. A beefed-up X-brace proved equal to the job, and quickly became the industry standard for the flat-top steel string guitar.
At the end of the 19th century Orville Gibson was building arch-top guitars with oval sound holes. He made the steel-string guitar with a body constructed more like a cello, where the bridge exerts no torque on the top, only pressure straight down. This allows the top to vibrate more freely, and thus produce more volume. In the early 1920s designer Lloyd Loar joined Gibson, and refined the arch-top jazz guitar into its familiar form with f-holes, floating bridge and cello-type tailpiece.
The electric guitar was born when pickups were added to Hawaiian and jazz guitars in the late 1920s, but met with little success before 1936, when Gibson introduced the ES150 model, which Charlie Christian made famous. With the advent of amplification it became possible to do away with soundbox altogether. Appleton constructed the very first solid body guitar. But that as it may, the solid body electric guitar was here to stay.
