_____________________ bits are used when some rocks are so abrasive that steel bits have to be replaced after they have been drilled only few centimetres of hole.
_____________________ bits are used when some rocks are so abrasive that steel bits have to be replaced after they have been drilled only few centimetres of hole. Correct Answer Carbide insert bits
The actual drilling points in case of carbide insert bits consists of very hard metal, tungsten carbide, which is embedded in steel. These bits are considerably more expensive than Steel bits.