Medium-sized PCB tungsten steel (carbide) drill bits typically range from 1.0 mm to 2.0 mm in cutting diameter with a standard 3.175 mm (1/8-inch) shank. They offer high rigidity and wear resistance for drilling fiberglass (FR4), circuit boards, and plastics on CNC routers.

Material: Solid tungsten carbide (tungsten steel) for extended edge life.
Shank Diameter: Uniform 3.175 mm (1/8") to fit standard CNC collets.
Size Range: Medium sizes span roughly 1.0 mm up to 2.0 mm (stepping up from micro-bits <0.9 mm and before large bits >2.1 mm).
Application: FR4 boards, acrylic, plastics, and soft metals

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