Comments by "Antony Wooster" (@antonywooster6783) on "Machine Thinking"
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I worked for a short while in Central Instrument-making workshop of the Akademie der Wissenschaften in Ardlershof, Berlin. In the DDR at that time, they had difficulty in getting the screws they needed, so they made their own. They had a huge encyclopedia-like book called "Deutscher Industrie Normen" Which specified, in enormoous detail the dimentoins and tolerances of everything imaginable. It even specified the radius of the bevel on the edge of the screwdriver-slot in the head of a screw. The tool that they used for making these screws was a special lathe, the headstock of which, together with the chuck gould slide towards or away from the tailstock. On the outer end of the headstock you could mount what they called "Ein Patron" (a cartridge) which was an externally threaded tube made of hard steel. about 3cms in diameter, this cartridge was matched by another piece, I think it may have been bronze which was half a nut of the same pitch. This half-nut was easily mounted on an arm which pivoted about a shaft mounted on the lathe bed. The simple v-shaped or square-shaped cutting tool was mounted on the cross-slide, which had a simple handle to push the cross-slide in as far as the adjustable stop would allow. In use, the stop was set for the first cut, the tool was pushed as far as the stop would allow, the headstock was set to rotate and the half-nut was engaged with the cartridge. The work piece then moved forward towards the cutting tool and the first cut was made. When the half nut was disengaged from the carteidge, the headstoch was pulled back to its resting place and the cutting tool was retracted at the same time Then the stop was reset and and the next cut was made. The screw-blanks were made on a standard capstan lathe as a seperate operation. It was surprisingly quick and easy to use this machine.
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