2018 E-Z Drill Inc. 210B, Dowell Drill, Drill 5/8- to 2-1/2-inch holes 18 inches deep in a 4-foot patch with the only on-grade drill on the market with these capabilities – the 210B. It requires just 100 cfm to operate, and the dual-purpose guide wheels transition simply from on-grade positioning to easy transportation around the jobsite. With its adjustable drill height you can drill into the center of slabs that are 6 to 24 inches thick.