An International Textbook Co. instruction paper (section 58) on undercam loom attachments for three- to six-harness work. It explains how cams are constructed for 3/1 twill, 2/2 twill and five-harness satin, and how auxiliary shafts and gearing give the right cam speed. It then covers harness rolls and strap arrangements, plain and tape selvage motions, side cams and continuous take-ups. The paper includes construction diagrams, gear calculations and examination questions.