www.thedriller.com/articles/86659-drills-with-grouped-hammer-and-bit-design

Drills with Grouped Hammer and Bit Design

March 1, 2005
New Cluster Drill Systems from Halco America Inc. offer a grouped hammer and bit design. Designed for performance and flexibility, they range from 20 inches to 72 inches in diameter and operate with minimal clearance. Off-the-shelf spare hammer parts are available. Halco America Inc., Card No. 307