How A Diamond Splinter Become The Most Accurate Cutting Tool On Earth

In 1942 a British trade journal warned that it was extremely doubtful whether any user of industrial diamonds could judge a stone's quality by sight. 43 years later, a diamond the size of a half-carat engagement ring sat at the tip of a lathe the National Bureau of Standards judged more accurate than an interferometer operating in air can measure. This documentary follows the diamond cutting tool from the splinters Roman gem engravers set in iron to the synthetic single crystal, and shows how each era made, held and sharpened the stone. It covers: Pliny's diamond splinters and the diamond drills found in beads from Arikamedu, India Jesse Ramsden's 1779 screw, cut after hardening with a tool pointed with a diamond carbonado, the black Brazilian diamond, and Rodolphe Leschot's diamond core drill at Mont Cenis Max Clausnitzer's 1892 shrink-fit setting tungsten wire dies drilled with a sewing needle, and the carbide those dies inspired diamond tools in the engine plants, and Wilhelm Winter's screw-set holders the wartime setters: J. K. Smit, Peter Neven's move to Gloucester, Koebel's 45-second press and Service Diamond's replaceable insert the De Beers stockpile suit and the National Bureau of Standards' spark-drilled dies Project Superpressure, Lach Diamant of Hanau, and sintered diamond cut by spark and brazed into carbide Y-12, Livermore and the single crystal tool, from microtome knives to the Large Optics Diamond Turning Machine why diamond wears on steel, and how it turns brittle crystals like germanium and silicon lapping along the soft direction, RCA's videodisc styli, X-ray orientation and Sumitomo's synthetic tool stone how a single crystal tool is lasered, lapped, vacuum brazed and relapped today Subscribe to Trade Archive for more stories about the tools, shops and people behind the trades:    / @tradearchive   Sources Clausnitzer, Max. Process of Setting Rough Diamonds, etc., in Holders or Implements of Metal. US Patent 486,084, filed April 8, 1892, and issued November 15, 1892. Duke, W. L., and R. T. Lovell. "Regrinding and Relapping of Single-Point, Single-Crystal Diamond Turning and Boring Tools." Oak Ridge, TN: Y-12 Plant, 1982. Estler, W. Tyler, and Edward B. Magrab. Validation Metrology of the Large Optics Diamond Turning Machine. NBSIR 85-3182. Gaithersburg, MD: National Bureau of Standards, 1985. Gorelick, Leonard, and A. John Gwinnett. "Diamonds from India to Rome and Beyond." American Journal of Archaeology 92, no. 4 (1988). Grodzinski, Paul. "Diamond Tools, Part 1." Aircraft Production 4, no. 41 (March 1942). Hale, Layton C. Principles and Techniques for Designing Precision Machines. UCRL-LR-133066. Livermore, CA: Lawrence Livermore National Laboratory, 1999. Kerr, Paul F., Donald L. Graf, and Sydney H. Ball. "Carbonado from Venezuela." American Mineralogist 33 (1948): 251-255. Liu et al. "Recent Advances in Design and Preparation of Micro Diamond Cutting Tools." International Journal of Extreme Manufacturing 6 (2024). "The Manufacture of Diamond Tools." Aircraft Production 4, no. 46 (August 1942). Moss, Herbert I. Method for Lapping Diamond. US Patent 4,532,737, filed December 16, 1982. Obata, Kazushi. "Single-Crystal Diamond Cutting Tool for Ultra-Precision Processing." SEI Technical Review, no. 82 (April 2016). Oomen (Philips). US Patent 5,078,551, issued 1992. Peters and Harris (National Bureau of Standards). US Patent 2,552,582, filed December 23, 1946, and issued May 15, 1951. Pliny the Elder. Natural History, Book 37. Translated by H. Rackham, W. H. S. Jones and D. E. Eichholz. Ramsden, Jesse. Description of an Engine for Dividing Strait Lines on Mathematical Instruments. London, 1779. Saito, Theodore T. "Diamond Turning: Opening a New Laser Design Door." FJSRL-JR-80-0003. 1980. Sechi, Yoshihisa, and Kazuhiro Nakata. "Dissimilar Laser Brazing of Single Crystal Diamond and Tungsten Carbide." Transactions of JWRI 39, no. 2 (2010): 340-342. Stone, James M., and Rutherford H. Taylor. Art of Setting Diamonds and Making Diamond Tools. US Patent 2,170,164, filed February 17, 1938, and issued August 22, 1939. US Geological Survey. "Industrial Diamond in the 20th Century." In Minerals Yearbook 2000. Reston, VA: USGS. US Geological Survey. Mineral Commodity Summaries 2025: Diamond (Industrial). Reston, VA: USGS, 2025. Walter, K. Science & Technology Review. Livermore, CA: Lawrence Livermore National Laboratory, April 2001. Yan, Jiwang, Kazuo Syoji, and Jun'ichi Tamaki. "Some Observations on the Wear of Diamond Tools in Ultra-Precision Cutting of Single-Crystal Silicon." Wear 255 (2003).