Builders FirstSource - Shafter [Production Operator / Assembly Line Worker] As an Assembler at Builders FirstSource, you'll: Perform one or more repetitive jobs on an assembly or sub-assembly line to produce building material components or millwork products; Assemble building material components such as wall panels, roof and floor trusses and/or millwork products; Perform insertion or positioning of materials, clamping, splicing, fitting parts...Hiring Immediately >>