Technical Gundrilling Information

• Gundrilling is a highly flexible, efficient and quick method of producing deep or shallow holes. Producing close-tolerance holes with smooth surface finishes, usually in one pass. This often eliminates the need for reaming, honing, or other finishing operations.
• Less known are the potential advantages of shallow hole and deep hole gundrilling. Depending on the material and application, gundrilling is always more precise, and often faster than conventional drilling.
• Tolerances as close as 0.0003" have been consistently held and surface finishes of 16 to 20 micro-inches are expected in gundrilling. Many different types of materials are used in projects ranging from cast iron to tool steel with hardnesses up to 46 R/c.
• When gundrilling, secondary operations such as deburring, reaming and work hardening are eliminated.
• Cast iron, aluminum, brass, molybdenum, steel, heat-treated stainless, polycarbonates, plastics, and many other materials too tough to twist drill normally are easily gundrilled.
• Because of the chip formation specific to gundrilling, chips can be discharged continuously from the cutting area by a high pressure coolant saving machine time. This allows holes to be drilled with no pecking 2 to 6 times faster than conventional drilling. Deep holes with 100 to 200 times the diameter can be drilled in a single pass.
• Cost savings when gundrilling occur in part because of long tool life. The gundrill can be reground 40 to 60 times on universal tool grinders by specially trained machinists. This long service life also makes it cost-competitive against twist drills.