[SIZE] - 3.9mm diameter, 75mm length twist drill bit with 3.9mm shank.. [MATERIAL] - Diamond-coated high-speed steel is made by spiral technology, has both toughness and hardness and is not easy to break. The drill bit is sharp and is easy for chip removal.. [APPLICABLE MACHINE] - Widely used in rotary tools such as hand drills, drill press, flex shafts, bench drills, and hanging mills.. [APPLICATION] - Suitable for drilling small holes in glass, metal, sea shells, jade, pearls, marble, stones, drywall and so on. Due to the different hardness of the material, the effect is also different.. [NOTICE] - When drilling, it is necessary to add cutting fluid in time to lubricate and cool down, which can get a better drilling hole wall, extends the service life and drilling accuracy..
