Chapter 3: Tools and Supplies
Construction tools are the things you use to fashion the frame and other mechanical parts the robot. These include a hammer, a screwdriver, and a saw. We will look at the tools needed to assemble the electronics later in this chapter.
No robot workshop is complete without the following:
- Claw hammer. These can be used for just about any purpose you can think of.
- Rubber mallet. For gently bashing together pieces that resist being joined nothing beats a rubber mallet; it is also useful for forming sheet metal.
- Screwdriver assortment. Have several sizes of flat-head and Philips-head screwdrivers. It's also handy to have a few long-blade screwdrivers, as well as a ratchet driver. Get a screwdriver magnetizer/demagnetizer; it lets you magnetize the blade so it attracts and holds screws for easier assembly.
- Hacksaw. To cut anything, the hacksaw is the staple of the robot builder. Buy an assortment of blades. Coarse-tooth blades are good for wood and PVC pipe plastic; fine-tooth blades are good for copper, aluminum, and light-gauge steel.
- Miter box. To cut straight lines, buy a good miter box and attach it to your work table (avoid wood miter boxes; they don't last). You'll also use the box to cut stock at nearperfect 45° angles, which is helpful when building robot frames.
- Wrenches, all types. Adjustable wrenches are helpful additions to the shop but careless use can strip nuts. The same goes for long-nosed pliers, which are useful for getting at hard-to-reach places. One or two pairs of Vise-Grips will help you hold pieces for cutting and sanding. A set of nut drivers will make it easy to attach nuts to bolts.
- Measuring tape. A six- or eight-foot steel measuring tape is a good length to choose. Also get a cloth tape at a fabric store so you can measure things like chain and cable lengths.
- Square. You'll need one to make sure that pieces you cut and assemble from wood, plastic, and metal are square.
- File assortment. Files will enable you to smooth the rough edges of cut wood, metal, and plastic (particularly important when you are working with metal because the sharp, unfinished edges can cut you).
- Drill motor. Get one that has a variable speed control (reversing is nice but not absolutely necessary). If the drill you have isn't variable speed, buy a variable speed control for it. You need to slow the drill when working with metal and plastic. A fast drill motor is good for wood only. The size of the chuck is not important since most of the drill bits you'll be using will fit a standard 1/4-inch chuck.
- Drill bit assortment. Use good sharp ones only. If yours are dull, have them sharpened (or do it yourself with a drill bit sharpening device), or buy a new set.
- Vise. A vise is essential for holding parts while you drill, nail, and otherwise torment them. An extra large vise isn't required, but you should get one that's big enough to handle the size of the pieces you'll be working with. A rule of thumb: A vice that can't close around a two-inch block of metal or wood is too small.
- Safety goggles. Wear them when hammering, cutting, and drilling as well as any other time when flying debris could get in your eyes. Be sure you use the goggles. A shred of aluminum sprayed from a drill bit while drilling a hole can rip through your eye, per manently blinding you. No robot project is worth that.
If you plan to build your robots from wood, you may want to consider adding rasps, wood files, coping saws, and other woodworking tools to your toolbox. Working with plastic requires a few extra tools as well, including a burnishing wheel to smooth the edges of the cut plastic (the flame from a cigarette lighter also works but is harder to control), a strip-heater for bending, and special plastic drill bits. These bits have a modified tip that isn't as likely to rip through the plastic material. Small plastic parts can be cut and scored using a sharp razor knife or razor saw, both of which are available at hobby stores.
There are a number of other tools you can use to make your time in the robot shop more productive and less time consuming. A drill press helps you drill better holes because you have more control over the angle and depth of each hole. Be sure to use a drill press vise to hold the pieces. Never use your hands! A table saw or circular saw makes it easier to cut through large pieces of wood and plastic. To ensure a straight cut, use a guide fence or fashion one out of wood and clamps. Be sure to use a fine-tooth saw blade if you are cutting through plastic. Using a saw designed for general woodcutting will cause the plastic to shatter.
A motorized hobby tool, such as the model shown in Fig. 3.1, is much like a handheld router. The bit spins very fast (25,000 rpm and up), and you can attach a variety of wood, plastic, and metal working bits to it. The better hobby tools, such as those made by Dremel and Weller, have adjustable speed controls. Use the right bit for the job. For example, don't use a wood rasp bit with metal or plastic because the flutes of the rasp will too easily fill with metal and plastic debris.
A RotoZip tool (that's its trade name) is a larger, more powerful version of a hobby tool. It spins at 30,000 rpm and uses a special cutting bit-it looks like a drill bit, but it works like a saw. The RotoZip is commonly used by drywall installers, but it can be used to cut through most any material you'd use for a robot (exception: heavy-gauge steel).
Hot-melt glue guns are available at most hardware and hobby stores and come in a variety of sizes. The gun heats up glue from a stick; press the trigger and the glue oozes out the tip. The benefit of hot-melt glue is that it sets very fast-usually under a minute. You can buy glue sticks for normal- or low-temperature guns. I prefer the normal-temperature sticks and guns as the glue seems to hold better. Exercise caution when using a hot-melt glue gun: the glue is hot, after all! You'll know what I'm talking about when a glob of glue falls on your leg. Use a gun with an appropriate stand; this keeps the melting glue near the tip and helps protect you from wayward streams of hot glue.
A nibbling tool is a fairly inexpensive accessory (under $20) that lets you "nibble" small chunks from metal and plastic pieces. The maximum thickness depends on the bite of the tool, but it's generally about 1/16 inch. Use the tool to cut channels and enlarge holes. A tap and die set lets you thread holes and shafts to accept standard-sized nuts and bolts. Buy a good set. A cheap assortment is more trouble than it's worth...