PROJECT 3: Drilling and Tapping Holes

Now that you've got the armor/structure plates cut out, you need to drill holes in them so that they can be connected together. This project will introduce you to techniques for using the drill press and cordless drill, as well as methods for tapping holes. You will be drilling holes into the aluminum base plate you cut in Project 2, as well as the Lexan side panels. You will also create threaded mounting holes in these pieces, so that you can assemble them in the next project.

Caution: Eye protection is mandatory for these tools. Pieces of metal will be flying everywhere. Review all of the general power-tool safety protocols described in Chapter 5 of Kickin' Bot (Cutting Metal), as well as the sections in Chapter 7 (Drilling and Tapping Holes) that correspond to the specific tools used below.

Part 3: Drilling the Top and Front Holes in the Side Panels

Continuing your work on the Lexan side panels, you'll be drilling the 1/4" through holes in the front and back armor pieces. Then you'll drill all of the mounting holes in the top and bottom of each panel, and tap them to form a screw thread.

click on an image to enlarge it

Drill the through holes in the panels marked "front" and "back" using a 1/4" drill bit. There are four 1/4" holes in each panel.

Drill the top and bottom holes all of the panels by clamping them into a drill press vise and securing the vise to the drill press table. Although the tapped holes will be for 1/4"-20 screws, you will be using a #7 drill for these operations (not 1/4"), because tapped holes require a smaller hole to form the threads.

After lining up and drilling the first hole, you can quickly set up for drilling the next hole by simply loosening the vise and moving the panel over.You can leave the vise clamped to the drill press table.

Using the techniques described in Chapter 7, tap the top and bottom holes with a 1/4"-20 spiral-point tap.

Although you can save a lot of time by using a cordless drill instead of the tap wrench to tap holes, I can't officially recommend it as a standard technique because it increases the likelihood of breaking the tap. (This is a personal choice for you.) With a large, strong 1/4"-20 tap like this, you probably won't break it, but it's much safer to use the tap wrench.

Chamfer all holes with a countersink, using light pressure as mentioned before.

Don't forget to chamfer all of the holes on the top and bottom. You can clamp the plates in a vise to hold them upright. Make sure to put some masking tape on the jaws of the vise so you don't mar the plastic.

Remove the patterns with Goo Gone or another solvent. Avoid acetone with Lexan, as it may attack the plastic, leaving a hazy finish.

At the end of this project, you should have an aluminum base panel with several holes (some of them threaded), as well as four Lexan panels with holes for the sides, front, and back of the robot.