Part 5 of an International Correspondence Schools instruction paper on silk throwing, covering doubling and spinning (twisting) of raw silk. It describes the construction and operation of vertical doublers and of first-time and second-time spinners and twisters: frames, stop-motions, spindles, bobbins, take-up rolls, traverse motions, belts, guides and flyers. It also covers twist direction for organzine and tram, and ends with examination questions. Illustrated with mechanical line drawings.