* Actual hand drilling test results in 1/4" thick mild steel plate: A 5/8 Roto-Cut Ultra™ completes a hole in about 25 seconds, a 5/8 drill bit re quires about 4 minutes. A 1-3/8 Roto-Cut Ultra™ completes a hole in about 85 seconds, a 1-3/8 drill bit re quires about 12 minutes.