Tools of the Trade

It's hard to decide which is more fun: building robots, or just playing with the tools used to build robots. In any case, I'll let you decide. While you're thinking about it, here's a review of tools -- both required and optional -- for the robot-building craft. To make this chapter all the more relevant, included are useful buying hints and tips, and how many of the tools are used in building automatons.

Of course, there are many additional tools not listed here: the mill, the lathe, the reciprocating hole saw, the scroll saw, the bandsaw, the welding rig, and literally hundreds of others. This chapter does not attempt to discuss every tool you're likely to use, but rather those common tools that are both the most affordable and the most practical for the average robot builder. You can think of this chapter as "If Bob Vila built robots, these are the tools he'd probably use."


Basic Tools

The following tools are considered "must-haves" for any robot workshop. Except for the drill, all are hand-operated, and most are likely ones you already own.

Safety Glasses

Important eye protection against flying debris. Wrap-around style provides the best protection. Use clear lenses for indoors; shaded lenses outdoors in sunlight. Purchase a pair for everyone who will be in the shop area while tools are in use.

I can't stress enough the importance of using adequate eye protection. I'm fortunate enough to have both of my eyes, but I came close to losing sight in one eye from flying debris. As a result, in my workshop eye protection is now mandatory for myself and all helpers.


Tape Measure

Retractable 6-12 foot is most convenient. Graduations in both inches and metric can be helpful, but is not critical. A paper or fabric tape (one yard long, available at yardage or hardware stores, often for free) can substitute in a pinch, but may not be as accurate.

Augment the tape measure with one or more wooden rulers purchased at an office supply store or "dollar" store. Cut them to length as needed, and mount on tools or workbench.


Screwdrivers

Set with slot and Phillips, in different sizes, preferred. At a minimum, get #1 and #2 Phillips, and medium- and small-tip slotted drivers. Magnetic tips are handy, but not necessary.

Purchase a good set, and test the grips for comfort. The plastic of the grip should not dig into your palm. Try soft (rubber) coated grips for extra comfort. Miniature fasteners (those 4-40 and under) require smaller screwdrivers. Purchase a set of #00 and #0 Phillips, and small-bladed slotted "jeweler's" screwdrivers.


Standard pliers
Needle nose pliers

A pair each of standard and needle nose pliers is sufficient for 90% of all jobs, though avoid using either as a wrench for tightening bolts and nuts (they'll strip the head of the fastener).

For heavy duty applications, purchase a larger pair of needle nose pliers. A pair of "lineman's" pliers can be used for the big jobs, and they provide a sharp cutter for clipping non-hardened wire (don't use them to clip steel aircraft cable or music wire).

I once bought a selection of five or six needle nose pliers, each with a different jaw style (thick, thin, rounded, square, etc.). The special jaw styles are handy every once and a while, but as a whole, I use the standard needle nose pliers over 95% of the time, and the others collect rust. Your mileage my vary.


Adjustable wrench

Often misnamed a "crescent wrench," after Crescent, a popular trade name, adjustable wrenches are used to tighten fasteners of various sizes. One small wrench (opening to about 1/2") and one large wrench (opening to about 1") suffice for most jobs.

Adjustable wrenches are usually sold by handle length, but this isn't as important as jaw opening size. Cheaper models don't open as wide. A jaw opening of 1/2" is the minimum you should consider; this size fits hex nuts up to 5/16.

The adjustable wrench is one tool where quality counts: get the best you can. Go ahead and spend $10 on a really good wrench. It'll be worth it, and the tool, when used properly, will last your lifetime. (In fact, many of the quality hand tool brands come with a lifetime warranty from the manufacturer. Even if the tool breaks, you can get a free replacement.)"

Bargain-basement" adjustable wrenches are actually harder to use and can cause damage to fastener heads, because they can slip and burr up the metal. Personal tip: avoid the "self-adjusting" versions of this tool. I haven't met one that really worked.


Locking grip pliers (Vise Grips)

Useful when your hand strength isn't enough. Vise Grips is the most common brand, and recommended for best quality. I bought several pairs of Vise Grips when I was a young man. I'm not so young anymore, but my Vise Grips are still like new. (And no, they didn't pay me to say this! I just like good tools.)

\Locking pliers come in a variety of shapes, styles, and sizes. For tight budgets, get one medium-size pair in the style shown. A smaller pair, as well as pair with needle nose jaws, can be handy, but are not critical purchases.

A word of caution: It's very easy to over-tighten the jaws of the pliers, and wreck the material you're working with. Tighten the jaws only so that they firmly hold the work piece, and no more. When squeezing the handles of the pliers the jaws should lock around the work piece with minimal effort. If you need to squeeze very hard, the jaws are too tight.


Water pump pliers

Also known as slip-joint pliers, this wrench is useful for gripping a variety of work pieces. Avoid using this tool for tightening fasteners; the wrench can cause damage to fastener heads. Like adjustable wrenches (above), purchase the best quality you can. Cheap versions slip, causing damage to the work, and injury to you. I can show you the scars on my knuckles, if you're interested...

Personal tip: avoid the "self-adjusting" version of this tool.


Hammer

Actually not often used in building robots except to whack parts to shape, or to demolish a robot that doesn't behave. Though most robots are not made with nails, a standard 16-ounce hammer is a useful tool for any workshop.


Hacksaw

A mainstay of robot building, purchase at least one hacksaw, if not several, with sturdy metal frames. Look for models that allow quick blade changes, yet hold the blade securely. Common blade sizes are 10 and 12 inches in length, and many hacksaws are adjustable. The smaller size is recommended when working with metal, as the short blade gives you more control of the tool. Purchase an assortment of carbide-tipped blades in 18 and 24 teeth-per-inch (tpi). If you have several hacksaw frames, keep blades of different tpi in each one. Even good quality hacksaw frames are fairly inexpensive.

Work tip: select a blade tpi so that a minimum of 3 teeth, but not more than 5 or 6 teeth, engage the work. If fewer teeth engage, cutting will be tough and coarse. If more teeth engage, chips from the work will gum up the blade and dull it. As a general rule, soft or heavy jobs need a coarser tooth pitch; harder, thinner materials need a finer tooth pitch. Periodically inspect the teeth of the blade, especially if you're cutting metal. If teeth are missing, replace the blade. Trying to cut with a damaged blade only makes you work harder to compensate for the ineffectiveness of the saw.

By convention, hacksaw blades are inserted so that the teeth face forward. Therefore, the saw cuts when you push the blade away from you. However, there is no strict rule that requires you to load the blade in this way. Experiment to see what suits the materials you are cutting. You may find that you have better control over the saw when cutting small pieces when the blade is mounted with the teeth facing you (saw cuts when you pull the blade toward you).


Electric Drill

An electric motorized drill with a 1/4" or 3/8" chuck is preferred, but a hand-operated drill will suffice for limited work. Chuck size determines maximum diameter for shank of bit. The vast majority of work on small robots will require bits of 1/4" or smaller.

For greater flexibility, opt for the 3/8" chuck; the big 1/2" chuck is seldom needed, because many larger drill bits use "stepped" shank bits, where the shank is 1/4" or 3/8", even if the bit itself is larger.



Drill bits

Purchase a variety, in so-called "jobber" length. Tungsten carbide-tipped and cobalt steel bits last longer, but are harder to re-sharpen at home. A basic set of steel twist drills will last many years when properly cared for. You can sharpen these on a grinder, or purchase an inexpensive drill sharpening tool.

The typical fractional drill bit set contains 29 bits, in sizes from 1/16" to 1/2", in 64ths-of-an-inch steps. For most robotic creations, you'll use only a third of these, but it's nice to have the full set in case you ever need the others. For the ultimate in long-lasting tools, purchase a set of titanium (technically titanium nitride) coated drill bits. These bits are said to last up to six times longer than standard high speed drills. An advantage of titanium bits is that they run cooler than standard steel bits. Still, when drilling steel it's still a good idea to squirt on a little cutting oil to make the job go easier. Even without the oil, the bits don't expand as readily, so the holes you drill are more accurate. You can get this oil at any hardware or tool store that sells quality drill bits.

Standard twist bits can be used for wood, metal, and many plastics, and have a 118° point. Steeper angle bits (135° split point) are used to drill into hardened and rounded stock. Specialty bits are available for drilling larger holes in wood (also shown here), and for drilling in acrylic plastic without cracking it. These bits use a modified tip and flutes to facilitate drilling into plastic.

Buying tip: purchase a standard 29-bit fractional drill set in standard high speed steel, then augment that set with specific sizes of more expensive longer-lasting bits.


Rasps and files

Rasps are used to remove large amounts of material from the work; files are for finish work. There are an estimated 3,000+ shapes, sizes, and styles of rasps and files, so it's best to purchase a general purpose set as a starter. A typical set includes one each round, half-round, square, triangle, and flat file, in lengths from 5 1/2" to 10".

Note that files are available for either woodworking and metalworking; they're different enough that you'll want to pick one over the other. Select a set based on the material of your robot. Plastics can make use of most metalworking files, though clean your tools regularly to remove any plastic material caught in the file teeth. Use a metal file brush for cleaning.

Personal tip: Jewelers files are miniature versions of standard-size workshop files. Sets are available with flat, half-round, round, and triangular files, and are available from specialty tool outlets. I use my jewelers files far more than the shop files.


Hex wrenches

Also called Allen wrenches, after the company that helped popularize them, hex wrenches (or hex "keys") are used with specialty hex head fasteners, particularly miniature set screws. Wrenches are available in fractional inch and metric sizes. You can purchase hex wrenches separately in various sizes, or in sets.

Personal tip: I find it difficult to use the all-in-one hex wrench where the individual wrenches cannot be separated from the set. Though you might on occasion misplace an individual wrench, separate tools are far easier to use, especially in cramped spaces. This said, if you own both metric and fractional inch sets, keep them separate. The wrench sizes between the two are similar but not identical, and it's easy to accidentally use the wrong size of hex wrench, leading to damage to the wrench and/or fastener.


Adjustable square

Squares are used for aligning frames and parts in robots. A basic adjustable 12" square is satisfactory for the job. Purchase a square with a metal, and not plastic, rule. Some models come with one or more bubble levels; this isn't an important feature.Work tip: Keep the rule lubricated with thin machine oil (such as 3-In-One household oil). The film of the oil will inhibit rust.


Razor knife

Sometimes called a carpet knife, a razor knife with a replaceable blade is used to cut thin plastic, rubber, paper, and other materials. Get the kind where the blade retracts into the handle for safekeeping.When cutting sheet material, be sure to back it with a soft surface, or else the blade will become dull, and you'll mar up the floor or table. A piece of 1/4" foam board does nicely.


Electronic Construction Tools

These are tools of the trade for electronics construction. Of the tools listed here, only the soldering pencil and meter (either digital or analog) are truly required. The rest are optional.

Not listed are several hand tools commonly found on the electronics workbench. These include the wire stripper and wire cutter, both of which are fairly straight-forward and need little discussion here. Buy 'em as you need 'em.

Soldering pencil

Used for all routine soldering of electronic and electrical parts. Do not use a soldering pencil of more than 30 watts, or the extra heat may damage components. Most soldering pencils come with a tip that's too broad for fine electronics work. Get a needle-point tip suitable for circuit boards.

Ungrounded (two-wire) soldering pencils are not recommended for digital circuitry. Purchase a grounded (three-wire) soldering pencil, and be sure the electrical outlet is also properly grounded. Get a soldering pencil with a replaceable heat element. You'll save money in the long run.

Personal tip: Though it adds $30-50 to the price, a soldering station with an adjustable heat setting is recommended. Smaller tips need less heat; by using a lower heat, the tip will last longer.


Soldering gun

Use an instant-on soldering gun when increased wattages are necessary for heavier duty jobs. This includes soldering large tabs on power terminals, or soldering metal parts together. Most soldering guns are about the same, and provide quick on-off heat at the press of a trigger.

Just remember: don't use these for delicate electronics. Soldering guns produce far too much heat, and will ruin many types of electronic components, particularly integrated circuits and transistors. Use a low-wattage (25-30 watt) soldering pencil instead.Be sure you can get replacement tips for the gun you purchase -- better yet, buy several while you can in case the gun is discontinued and its tips become hard to find.


Analog meter

Used to measure DC and AC voltages, amperage, resistance, and continuity. While looking older fashioned, analog meters are sometimes preferred as the needle is easier to read under different lighting conditions. Many analog meters are also capable of measuring higher amperages than their digital cousins.

Though only a minor advantage, nearly all analog meters do not require a battery to measure voltage and current (a battery is needed for testing continuity and resistance). This can be beneficial if you are out in the field, and the battery to the meter goes dead. Unlike a digital meter (see below), you can continue to use your analog meter for important measurements.


Digital meter

Used to measure DC and AC voltages, amperage, resistance, and continuity. Many models also test: capacitors, diodes, and transistors.

A handy feature found on nearly all digital meters is the audible continuity tester. If resistance is at or near zero ohms, the circuit is assumed to be closed, and a beep indicates continuity. Be sure the meter you get has this helpful feature.


Bench power supply

Use a bench power supply to provide consistent and clean power to your circuits as you develop them (once you're sure they work, you can run them off batteries).

For power supplies with non-adjustable outputs, a model with +5 and +12 volts dc will suffice. Each output should support at least one amp current, if not several amps. (You will need 3-4 amps, at 5 or 12 volts dc, to test most robot motors.)

For power supplies with adjustable outputs, a voltage of 2-12 volts dc is the recommended minimum. Ideally, the power supply should be equipped with its own meter that accurately displays the output voltage. If the power supply lacks a meter, you will need to use a separate volt-ohm meter to monitor the voltage output.


Oscilloscope

Definitely an optional item, an oscilloscope allows you to "see" an electrical signal. This tool is a must-have for circuit design and troubleshooting, but is not a requirement for general electronics tinkering. Opt for a model with no less than 30 MHz bandwidth. Dual trace, digital storage, and delayed sweep features are nice, but not absolutely necessary. You will, however, find a use for these features if your scope has them.Personal tip: PC-based oscilloscopes are often less expensive than full scopes, but require a computer in your shop. You must balance the need to have a PC nearby just to use your test equipment, and such a setup is not as portable. Also available are hand-held scopes. These tend to be expensive when they are fully equipped with features such as 50-100 MHz bandwidth, delayed sweep, and digital storage.If your budget is tight, try a used scope from eBay or from a reseller of used test equipment. Opt for one that comes with a money back guarantee unless you are confident you can fix it should it arrive in non-working order.


Specialty Hand Tools

What follows are hand tools you don't strictly need for building 'bots, but which you'll find are handy for more sophisticated designs.

Mallet

Standard rubber mallet -- nothing fancy. I prefer the two-headed mallet with both hard and soft rubber tips. Do note that the rubber can become damaged if you try to use the mallet as a hammer. The purpose of the mallet is to gently tap parts in order to seat or remove them. Using them as a sledgehammer will definitely shorten the life of the tool!

Work tip: Use a small block of wood between the mallet and part you want to loosen or set. The shock imparted from the mallet will transfer through the block, and into the part. There is less risk of damage with method, and the head of the mallet won't get as chewed up.


Hot melt glue gun

Comes in either "mini" or standard size; for standard size, get one that can use high temperature (as opposed to low temperature) glue sticks. A dual-temperature model is the all-around best bet, though these cost more.

The better glue guns accept different tips. The standard round hole tip is suitable for general glue application. With this tip you can apply a bead of glue that can be spread by exerting pressure on the parts being joined. Additional tips include the spreader applicator, available in different widths. This tip applies a wide coat of glue of a specific thickness, and is ideal when laminating materials.

You can purchase replacement glue sticks at hardware and home improvement stores, as well as most arts and craft stores. The latter also offers colored and glitter glue sticks; which you probably won't use much in your robot. Be sure to select the proper temperature glue sticks for your gun. High temperature sticks will not melt in a low-temp gun; and low temperature sticks are unnecessarily overheated in a high-temp gun.


Clamps

Assortment of C-clamps for holding pieces for drilling and gluing. Heavy duty spring clamps (they look like over-grown clothes pins) are handy for smaller jobs.

Get several of different sizes. Use the right size for the job. An oversized spring clamp can exert too much pressure and cause damage to the material you're working with.


Hobby knife

Interchangeable blades make the hobby knife, such as the X-Acto brand, a handy tool for cutting cardboard, foam board, and thin plastics.

A word of caution: the blades in these knives are extremely sharp. Use with care, and never leave the knife out in the open where children may play with it. If the knife does not have a blade cover (or does not retract), purchase a small plastic box for the blade and knife, and keep them safely stored there when not in use.

Though the blades are typically made of stainless steel, they can rust over time and exposure to the air. If you buy an assortment of blades for now and the future, apply a couple of drops of oil to them, them wrap the blades in cotton gauze, or in a plastic sandwich baggie. They'll last for years this way.


Socket and box wrenches

Socket wrenches make fast work out of tightening and loosening nuts and bolts. Standard-size sets for automotive work are usually too big for small mobile robots; get a miniature set in sizes more appropriate for the standard robot -- 2-15 mm for metric size, or #2 to 1/2" for Standard sizes.

Personal tip: Don't skimp on quality. A good set of socket wrenches should last you a lifetime. "Buy once, keep forever," is my motto.

Box wrenches are used for the same job, but except for certain brands, don't have a ratchet mechanism. They're useful for tightening nuts and bolts when space doesn't allow for a socket wrench.


Nut Driver

Tightens hex head nuts and screws. These look like screwdrivers, but are designed for use with hex nuts. Comes in metric and Standard sizes. On the Standard front, common driver sizes are:

Driver

For hex nut

1/4" #4
5/16" #6
11/32" #8
3/8" #10
7/16" 1/4
1/2" 5/16

Metal snips

Also called tin snips or aviation cutters, these tools are available in different versions for straight, right-hand, and left-hand cuts. Sees use in robotics for cutting sheet thin (to about 24 gauge) sheet-metal and up to 1/16" thick aluminum.

Heavier metal needs a suitable metal sheer, a foot or hand operated machine that can cut much thicker material.


Drill punch

Use to "set" a starting mark for drilling in wood or metal (not recommended for acrylic plastic, which can crack). A spring-loaded punch can be used without a hammer.

Use a sharp nail as an alternative. As needed, grind the tip to a sharper point. This will ensure a good mark in the material.


Tap and die set

Taps thread holes for bolts and machine screws; dies thread shafts for nuts. Select a set in standard or metric size, as needed. Don't go cheap; the inexpensive tap and die sets break and dull easily.

Assuming Standard sizes, purchase a set with 2-56 to 1/4-inch UNC (coarse) threads -- or purchase individual taps and dies as needed. Can also be used for thick plastics and non-ferrous (aluminum, brass) metals.

When tapping metal, even aluminum, it's always advisable to use tap threading oil for lubrication (the same oil can be used with dies). The oil helps reduce overheating and dulling of the tool, and makes the work much easier for you.


Table vise

Secure to your workbench to hold pieces while you cut and drill. A jaw opening of up to 4" is enough for most jobs.

Personal tip: Periodically apply a lightweight machine oil (e.g. 3-In-One) to the surfaces of the vise, then wipe off with a clean paper towel. The light film of oil inhibits rust.


Heavy duty stapler

Use to attach rubber or thin plastic to wood-framed robots. Boxes of staples, in different sizes, are available at any hardware store.

Why purchase a stapler like this when there's a perfectly good paper stapler in your desk? The problem with this line of thought it that the paper stapler doesn't impart the force necessary to drive a stapler into thick material, especially PVC plastics. What's more, the staplers themselves are thin wires; you want a heavier wire that can penetrate 1/4" or more of material.


Specialty Power Tools

As with the specialty hand tools, above, these are power tools that are not strictly required, but can greatly decrease the time and energy spent on constructing robots. "Required" is, of course, a subjective thing. Personally, I wouldn't do without any of the tools that follow. I use them all quite regularly.

Motorized screwdriver

Rechargeable and reversible models make short work out of most any job. You may want to purchase a couple of units so that you can use one while the other is recharging.

Eventually, your motorized screwdriver will give out, typically because the battery is no longer able to hold a charge. Don't throw the screwdriver away! Instead, hack it for its motor and gear box. Many motorized screwdrivers can be used as-is (without the battery compartment) as a drive motor for a robot. Mount the screwdriver to the base of the robot using clamps or even nylon tie-wraps. Wheel shafts or other power transmission components can be made using old power screwdriver bits (see below) and accessories.




Driver bits

Most motorized screwdrivers (see above) come with an assortment of driver bits. Purchase extra as needed. Available in common drive types: slotted, Phillips, square, Torx, and Pozidriv, each in several sizes.Also available are drill bits for making quick holes. These are commonly available in small sets, with drill bits from 1/8" to 1/4".


Dremel

The ubiquitous motorized hobby tool, the Dremel can be used as a miniature drill, sander, cutter, or grinder. Kits come with a variety of bits (most you'll never use), and additional bits are available for separate purchase. The 1/8" drill and miniature cut-off saw are among the most practical.

There are other brands of motorized hobby tools, but Dremel is by far the most popular.


Roto Zip

Originally intended for drywall installers, the Roto Zip is technically referred to as a spiral saw. The 1/8" bit is a combination saw and drill. Versions of the bit are available for soft materials, like sheetrock, as well as plastics and soft non-ferrous metals.

Note that a similar spiral-cutting drill/blade is available for the Dremel tool, and is used in much of the same manner. The Roto Zip is preferable when cutting thicker and heavier materials.


Drill press

A bench or self-standing drill press allows for more accurate holes. There is no need to spend lots of money here; an ordinary $75 to 150 model will suffice. If yours doesn't come with a drill press vise, purchase one separately -- about $30, or more if you want magnetic jaws. The jaws hold to the vise with magnetism, and are covered with rubber to protect the part you're drilling.

Nearly all drill presses are variable speed by adjusting the drive belt. High speeds can be used when working with wood, but slower speeds should be used with plastic and metal. You definitely want an adjustable speed model.

Handy, but not required, is electronic speed control. Rather than adjust the belt on a set of pulleys, you merely dial in the speed you want to use. This feature is helpful when altering between different materials, and between various sizes of bits (general rule: the larger the bit, the slower the speed). However, electronic speed control adds to the cost of the drill press.


Circular saw

A standard 7 1/4" circular saw can be used to make short work out of cutting wood and 1/4" or thicker plastic sheets. Be sure to use the correct blade for the type of material you are cutting. For straight cuts, purchase a saw fence, available at most hardware and home improvement stores.

The strongest circular saw is the worm drive, and is intended for cutting heavy lumber, such as the framing of a house. Worm drive saws are much heavier than the standard models, and unless you're build house-size robots, they aren't really needed. Save your money for other tools.


Table saw

A 7 1/4" to 10" table saw provides more accurate cuts than a hand-held circular saw. As with the circular saw, be sure to use the correct blade for the material you are cutting.

A word of mild caution is due: many hardware and home improvement sell economy table saws for under about $80 to $100. These saws will certainly cut through material, but they are not known for their accuracy, especially when carelessly assembled. Don't trust their guide fence; measure everything yourself with a carpenter's square. Periodically, recheck the alignment of the table, and make adjustments as necessary to ensure true, square cuts.

Alternatives to table saws include the bandsaw and the radial arm saw. Each type of saw has its own special place in the workshop. Personally, I prefer a radial arm saw for general cutting, but there are some jobs that are best handled by a good table saw.


Orbital sander

Orbital sanders are designed for finish sanding of wood, but they are also good general-purpose sanders -- when equipped with the proper sheet of abrasive -- for plastics and even non-ferrous metals. Mount the sander upside down in a vise to use it as a bench sander.

Sand papers are commonly available with grits ranging from a very rough 50 to over 300. Use a lower grit to remove large amounts of material; a higher grit to achieve a smooth finish. You can sand many soft plastics, such as expanded rigid PVC, with a 150-175 grit paper. Metal can be sanded using 250 to 300 grit wet/dry paper, used wet. The paper is wetted with ordinary water.



Jigsaw

Jigsaws are used to cut intricate shapes in wood, plastic, and thin sheet metal. The jigsaw is basically a motorized hacksaw, but is easier to use for inside cuts (like cutting a circle out of a sheet of wood). It is critical that you match the blade to the material you are cutting. See the note for hacksaws and blades, earlier in the chapter.


Miter saw

The motorized miter (or cutoff) saw is useful for quick and accurate cutting of rod, bar, channel, and angle stock. The saw can make straight cuts, or adjusted to make angle cuts. Miter cuts at 45 degrees are used to build frames. Use the appropriate blade if cutting ferrous or non-ferrous metals. I prefer a toothed blade rather than an abrasive cut-off blade. When using toothed blades for cutting metal, be sure to always use the appropriate blade lubricant, or else the life of the blade will be significantly reduced.

I make heavy use of my miter saw for cutting channel and angle aluminum for robot frames. Construction time is greatly reduced compared to using a hacksaw, and the finished product is much better. The cuts are straight (no "rounds" so common with manual hacksaw cuts), and the miter angles match perfectly. There is generally less "flash" (rough metal edges) to remove with the file and grinder.I

would have placed the miter saw in the "must have" category except that not everyone builds robots using aluminum stock. If you do, then by all means consider this an essential tool in your work.

Safety tip: Miter saws can be dangerous when cutting small pieces. Use a clamp to hold the piece on both sides of the blade when being cut. Exercise the usual cautions, and use protective eyewear and gloves at all time.



Router and router bits

The router is used to form special edges and grooves in material. In the woodworking shop a prime use of the router is to create joints for cabinets; for robotics, the router can be used to make grooves and raceways for wiring and parts, and to finish the edges of wooden and plastic frame robots. Most routers come with a small assortment of router bits. Augment this assortment with additional bits, as needed.

A note about successful use of routers: More than any other tool described in this chapter, the router requires the most skill to use properly. If you've never used a router before, don't expect professional-looking results the first time out of the box. Practice with scrap pieces. Routers turn at a very high speed (up to 30,000 rpm), and when used on 1/4" or 3/8" thick plastic and wood, the bits do their business very quickly. It takes skill to create the fine cuts and grooves that are the hallmark of the expert.


Grinder

The hand-held grinder is useful when working with ferrous and non-ferrous metals. It takes the place of hand files for removing burrs and flash. If you plan on doing lots of metal work, consider investing in a bench grinder. Models are available for under $50 that do a decent job. These attach to your workbench, and provide two grinding wheels, which are replaceable, on either side of the tool.

If you work with acrylic plastic, you can outfit one of the grinding wheels with a cloth polishing wheel. Purchase rouge or other polishing compound from a plastics special shop, and apply it to the spinning wheel. You may then polish the acrylic plastic to a bright shine.