5x5 drill/quarry, you can build it alot longer if you want to, Piston extension is 50 poles. In the picture and Schematic im using a creative motor. You can add another kind of power source.

All credit for this Schematic goes to Monkeyfarm!
https://www.youtube.com/channel/UCn2ySNr-W8ZSXlEsxONqUXw