PROJECT 2: Cutting the Armor Pieces

Cutting metal and plastic plates are essential skills for the robot builder, so we're starting there first. This project will get you working with the circular saw, jigsaw, and miter saw by cutting the armor and frame pieces for the project robot. While all of these cuts could be done with the jigsaw, I'll demonstrate some with the other two tools to show situations where their specialized designs allow you to make the cuts more quickly and precisely.

Caution: Eye and ear protection are mandatory for these tools. They are incredibly loud, and pieces of metal will be flying everywhere. Review all of the general power-tool safety protocols described in Chapter 5 of Kickin' Bot, as well as the sections that correspond to the specific tools used below.

Part 2: Cutting Metal Plates with the Jigsaw

For the second cut in the baseplate, you'll cut on the 14" line. This operation can also be performed with the jigsaw equipped with a non-ferrous metal cutting blade, as described in Chapter 5.

click on an image to enlarge it

For this cut, I'll demonstrate hanging the waste piece off the edge of the table. As in the previous example, you must measure the distance from the blade to the edge of the footplate as put your guide at that offset from the 14" cut line. Make sure to use the stick wax or WD-40 for lubrication.

Before starting, make sure to review the procedures for cutting metal with the jigsaw in Chapter 5. Begin your cut with the blade not in contact with the workpiece, and the footplate level. Let the blade get up to speed, and then slowly bring it into contact with the workpiece. In this setup, to prevent the blade from binding, you must hold up the waste piece by hand (as shown) as you near the completion of the cut. Make sure to keep your arm up and out of the way, and fingers clear of the blade at all times.

There will be some cleanup required after the cut with the belt sander. Make sure to hold the sander as perpendicular to the workpiece as possible, or the edge will be angled.

Take this edge to the deburring wheel and draw the ragged corner across the wheel in a smooth and steady motion, applying moderate and constant pressure. Make sure to line up to wheel below the center line. Make sure to get both the top and bottom edges. You can clean the remaining stick wax residue from the piece with Goo Gone and a rag.


The top armor will be made out of 1/4" inch thick polycarbonate. The top has the same dimensions as the base. You'll use the same cutting operations for the plastic top armor as you did for cutting the metal base. However, the most important thing is that you need to change lubricants. In plastic cuts, heat builds up rapidly, and you need a liquid coolant such as WD-40 or even water. To get the best results, you should keep the water or other coolant flowing into the cut. Instead of using the deburring wheel, you should use a flat file to chamfer all edges. The deburring tool (a hand-held tool) can also be used for this operation. Its usage is discussed in detail in Chapter 6 (Shaping and Finishing Metal) as well as in Project 4.