T38 76mm Flat Face Normal Body Dome Button Drill Bit The T38 76mm flat face normal body dome button drill bit is a threaded rock drilling bit designed for efficient and reliable drilling in mining, quarrying, tunnelling, construction and general rock excavation applications. Featuring a 76mm drilling diameter, T38 threaded connection, flat face design and normal body construction, this drill bit provides a balanced cutting structure for rock penetration and wear resistance.