INDEXABLE CARBIDE DRILLS USING TRIGON STYLE INSERTS HAVE SEVERAL DISTINCT ADVANTAGES OVER HIGH-SPEED STEEL AND SPADE DRILLS FOR ROUGHING APPLICATIONS. THERE ARE, HOWEVER, SEVERAL CONDITIONS THAT MUST BE MET TO USE INDEXABLE DRILLS EFFECTIVELY. THE MACHINE AND THE SETUP MUST BE EXTREMELY RIGID WITH ADEQUATE HORSEPOWER. PROPER CHIP CONTROL WITH GENEROUS AMOUNTS OF COOLANT IS ESSENTIAL. INDEXABLE DRILLS WITH TRIGON INSERTS PROVIDE HIGH STRENGTH, POSITIVE INSERT GEOMETRY, EXCELLENT CHIP EVACUATION, AND BALANCED CUTTING FORCES. THEY ALSO ARE RESISTANT TO TOOL DEFLECTION. INCLUDED IN THE REPORT ARE RECOMMENDED SPEEDS AND FEEDS, ALIGNMENT GUIDELINES, POWER REQUIREMENTS, AND TROUBLESHOOTING CHARTS.