Tool for originating screw threads, made by Henry Maudslay, 1800-1805

Henry Maudslay saw that accurate screw threads were the bedrock of precision in engineering, particularly in the lead screws of lathes which control the movement of the cutting tool. The problem he faced was how to make a perfect original master. This tool used an inclined knife to cut its own path in hardwood or soft metal blanks. These were then used as temporary lead screws in the Maudslay screw-cutting lathe as masters to form permanent lead screws in harder steels.