Boart Longyear

Handheld (short hole) Steel

This provides a hexagonal chuck section to provide leverage for the rotation chuck bushing. It usually has a forged collar to maintain the proper shank striking face position in the rock drill, and a tapered bit end. Tapered steel lengths—available from 0.6 m to 3.6 m in length—are measured from the collar to the bit end.

Holes are typically drilled in 0.6 m increments to accommodate the airleg feed length. The drilled steel is then extracted and followed with a slightly smaller diameter bit on the next steel length in the sequence.