Selecting the right tool depends heavily on the Rock Mass Rating (RMR) and Mohs hardness. For hard, abrasive rock, prioritize Tungsten Carbide (WC) inserts with high cobalt content for toughness. For softer formations, steel-bodied bits with larger flushing holes are more efficient. Ensure the thread type (e.g., R25, R32, T38, T45) is perfectly matched to your existing drill strings to prevent energy loss and thread stripping. Additionally, verify the flushing hole configuration to ensure optimal debris removal, which prevents regrinding and extends tool life.