Here the robot is spot drilling the main aluminum plates for the Lego powered camera rig. Spot drilling is the process of using a specialized, very stiff drill to create a starting point for a regular drill to go in and actually finish drilling all the way through. In this case, the spotting operation is only drilling 1/32 of an inch deep. If this part wasn't drilled in this two step process, the tip of the regular drill would hit the surface of the metal and "walk" a small distance in a random direction until it started actually biting in to the metal and making a hole. Obviously, this is not very accurate. On operations like drilling in to the side of a round cylinder - like drilling a pipe, spot drilling is VERY important if you want any kind of predictable result.