Drilling Square Holes 06 April 2018, 13:00 Sorry, your browser doesn't support embedded videos, but don't worry, you can download it and watch it with your favorite video player! Device for drilling square hole of rounded corners based on the principle shown in “Drilling square holes 2a” « previous mechanism Machine Tool Fixture next mechanism » Gear Rack Drive for Reversing Rotation load comments Please enable JavaScript to view the comments.