You're in the home stretch. This is the last project. Here, you will clean up loose ends such as adding strain relief and managing the antenna. Next, you'll tune the radio and perform your first test run. If all goes well, then you'll finish up the top armor, and tidy up the last few details before going into hardcore survival testing.
|Caution: Eye protection is required for all cutting, drilling, and grinding operations in this project. Caution: Review all of the general power- tool safety protocols described in Chapter 5 of Kickin' Bot (Cutting Metal), as well as the sections that correspond to the specific tools used below.|
Part 3: Holes in the Top
Before going into more serious testing, it's necessary to finish off
the top armor. You'll take the 1/4 inch thick piece of Lexan you cut way back in Project 2 and drill the perimeter
holes for mounting. Then, you cut access holes for the master and secondary power switches.
click on an image to enlarge it
|Peel off the protective coating on one side of the top armor. Print out and tape together the base pattern. The pattern for the perimeter holes is the same. Apply this pattern to the polycarbonate using spray adhesive.|
|Mark the perimeter hole positions with an automatic center punch. Drill the holes using a 17/64" drill bit, which is slightly oversize (1/64" larger) from the target ¼" hole size. Make sure to use adequate lubrication. Chamfer all the holes, top and bottom, with a countersink. Remove the pattern and get rid of any sticky residue with Goo Gone. Also remove the protective cover on the bottom of the plate.|
|Install the top armor on the robot with one or two screws on each side. Look through the clear top and visually mark the locations of the master power and secondary power switches with a marker. Use an automatic center punch to put a divot at each mark.|
|Clamp the plate to a table with a piece of scarp polycarbonate under each clamp to keep the top armor from getting scratched. Use a 3/8" drill bit for the master power switch and a large Uni-bit for the secondary power switch. Make sure to use adequate lubrication.|
|Clean up the plate and put it back on the robot. If you can't get all the screws in, then you can try the following trick: Get as many screws as you can going all at once. Make sure the plate is sitting flat on the robot. Chuck a tap (in this case, ¼"-20) into a cordless drill. Then retap the holes with the lid in place. This will actually thread the through holes a bit where they interfere, but will also allow you to get the screws in much easier. The trick is that the threaded hole will guide the tap. Since it's tapered, it won't start threading the through-hole until it's already started in the right thread.|
|Make sure all the screws fit, but don't tighten down the top cover just yet. There are a few more final touches that you'll need to perform in the next step.|