The Machine Shop is a one and a half story building that was built on Main Street around 1910. It is located on the site of what is believed to have been the stables of Doria Deighton Jones’ adobe home which was torn down in 1886, and was built by her daughter Constance Jones Simpson. The first tenants of the building were engaged in light industrial occupations such as tinsmithing, electroplating, metal patterning and machining. With the advent of the Mexican market place on Olvera Street in 1930, the uses of the Machine Shop were changed and the front doors were opened on Olvera Street, rather than Main Street. The first tenant was the Leo Carrillo Theatre, followed by the Olvera Street Puppet Theatre. The proscenium arch and a segment of the stage still survive.