Guhring 660-0.680 0.68mm DIN 1899 HSS-E-PM Micro Drill Bit (10pc)

This is a new pack of 10 Gühring S-Kleinstbohrer (micro drill bits), part number 660-0.680, conforming to DIN 1899 R-N, with a cutting diameter of 0.68 mm. The drills are manufactured from HSS-E-PM (powder metallurgy high-speed steel with cobalt), which provides significantly higher hardness, wear resistance, and red hardness compared to conventional HSS or HSS-E, making it the preferred grade for drilling hard, abrasive, or difficult-to-machine materials at micro scales. The gold-toned tip visible in the photos is characteristic of the TiN or surface treatment applied to Gühring PM-series micro drills, enhancing surface hardness and lubricity. DIN 1899 R-N designates a short-flute, straight-shank micro drill geometry with a nominal (N-tolerance) shank, intended for precision micro-drilling in watch components, PCB manufacturing, medical devices, jewelry, and instrument-making using high-speed spindles or precision drilling machines with collet-type chucks suited for sub-1mm shanks. Made in Germany.

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