b'Mod Squadsteel bar. In addition to its proprietary steel and heavy metal modular designs, Mulcahy said ARCH Cutting Tools offers two industry-standard mod-els in carbide and steel, with steel being the lower-cost option and carbide costing up to 500% more. However, steel is suitable only up to a 4-1 projection ratio without worry-ing about chatter or harmonics, he said. A heavy metal bar can hang out at a projection up to 6-1 while theARCH Cutting Toolstungsten-carbide one can achieveShown is a selection of boring heads and at least a 7-1 and potentially an 8-1Patriot High Performance Stealth boring bars projection when boring with a pos- by Ultra-Dex.itive insert.ARCH Cutting Tools also offersMulcahy noted. workpiece, such as when threading Patriot High Performance StealthAlthough the two smallest ratiosor grooving.boring bars by Ultra-Dex. The barscan be achieved without a dampingA lot of insert engagement cre-have internal damping devices andsystem, he said they are suitable forates the most harmonics, Mulcahy are available to achieve a 5-1, 7-1,applications in which theres signif- said. We recommend it because 10-1, 12-1 or 14-1 ratio projection,icant insert engagement with thethey will dampen harmonics that BIG Daishowa says its Smart Damper incorporates a damping mechanism and reduces chatter instantly. A unique dynamic damper eliminates chatter and achieves high-speed, high-efficiency machining for work requiring a long projection length.BIG Daishowa28JANUARY 2023 HoleFinishing.indd 28 12/15/22 1:35 PM'