Here is a job I did a few months ago. Had to predrill 5 holes 22' deep in NYC ti Install H piles. We predrilled the holes to a dept where the soil would not collapse and then installed temp. steel casings that we would drill inside and clean out and push down to we hit the top of bedrock. Had to truck in the Equipment after 10:00pm to get it in since it was an oversize load.Here is a V YouTube - Predrilling for H piles
did you know the driver John who delievered it? Went on a move and drove with him last winter
Yes I know the driver I was on site to load and unload the machine both times at night.