Small Gravity Powered Model Cars – Speed Tips

Ten Speed Enhancement Tips

Car Design - NASCAR and Indy race teams know all about the importance of aerodynamics. The same principles apply to gravity race cars. If you want to go fast, the car needs minimal air resistance. As crazy as it sounds, a simple wedge shape car solves this problem. Don't forget to slant the back of the car so it doesn't drag when the car hits the bottom of the hill.

Wheels - The wheels provided in the standard kit are excellent. They are usually very round and free of defects. Check for burrs on the outer edges. I always enlarge the axle hole by 1/64th of an inch so that the wheel can rotate freely on the axle.

Axles - Alignment is critical. The car's axles must be parallel and in the same plane. If they are out of alignment, the car will ride on three wheels and/or one or more wheels may be in a bind. This obviously creates friction and friction slows the car.

Grind / Polish Axles - The axles supplied with the kits are simply nails. The underside of the nail head contacts the outer surface of the wheel as it spins on the axle. If you grind the head of the nail so it flares away from the nail shaft, this means there will be less friction where the nail head touches the wheel. Polish the nail shaft with emery cloth to reduce surface friction on the wheel shaft.

Balance - The weight of the car needs to be as balanced as possible. This eliminates concentrated loads on one or more wheels. Unbalanced cars are also unstable on the race track. If they hit a slight bump, an unstable car can jump off the track.

Car Weight - Most gravity cars cannot exceed 5 ounces. The car body, wheels, axles, etc. only weigh a little over 2 ounces. I prefer to add weight by using lead. I create a recessed area on the underside of the car with a router. The recess is usually 1.25 inches wide, 2 inches long and about 5/16ths inch deep. Use a torch to melt stick or roll solder.

To add the correct amount of lead, you need to place the completed car body and all of its parts onto an accurate scale. Begin to add solder until you get to 5 ounces. If the car is deemed overweight at the check-in, you can shave off lead from this area.

Be sure to undercut the recess area slightly so the lead doesn't fall out.

Graphite - Dry powdered graphite is a superb lubricant. I like to puff some in the axles, wheels and even on the sides of the car body. Apply it any place where one moving part touches a stationary object.

Inner Wheel Hubs - The wheels that come with the kit have squared off hub shafts. These rub against the car body when the wheels spin. If you shave these slightly to make them rounded, only a small portion of the hub will actually contact the car body. Less contact = less friction.

Wheel Tilt - When the axles are mounted to the car body, the axles need to be straight. If not, the wheels will be tilted slightly. Use a small diameter carpenter's nail set to lightly drive the axles so they bottom out in the axle groove.

Last Minute Weight - If your car is light at the weigh-in and you add weight, do so on top of the car. Never add weights on the bottom that might allow the weight to drag on the race course track.

Last Minute Lubrication - Be sure to take your tube of powdered graphite with you on race day if you decide to do trial runs down the track. Lubricate all axles before you turn your car in. Spin the wheels while puffing graphite on the axle shafts.

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Building Derby Cars

The thrill of victory - the agony of defeat. Surely, you have heard those words spoken at the open of ABC's Wide World of Sports. If you want to see these emotions first hand, then attend a Girl or Boy Scout Pine Wood Derby! It is not uncommon to see alligator tears when a car doesn't win. Those children whose cars do win, jump and shout with glee!

Speed vs. Looks

This competitive event is as much for the parents as the kids I believe. Young scouts need lots of help to build the cars. As the kids get older, it is actually important for them to build their own. At the very least, the kids should always, always paint and decorate the cars themselves. Remember, it is their race, not the parents. But in some scout packs and troops, the leaders recognize that adults do build the cars. For this reason, they have a special race for cars built exclusively by adults.

Consider building a car for looks and creativity instead of speed. Different awards are often presented for looks.

Check the Rules

Certain race contests have certain rules. Some allow major modifications to the cars. Others allow minimal modifications. Never cheat. It simply is the wrong thing to do. If your child catches you, it sends a horrific message to them about you. Remember, no one wins any money!!! This is a kid's event, not the Daytona 500.

Lasting Memories

Building a car with your child should be a fun event. Don't ruin it by waiting to do it at the last moment. Start at least one week in advance, if possible to reduce stress. This past year both my son and daughter built cars with me. They had the best time coming up with the colors and painting on crude racing stripes. I am convinced that they will not forget the experience. One thing is for sure, they will not forget the loud hissing noise my plumbing torch makes as it melts the lead! It really frightened my son!

Display Stand

If your child stays in Scouts for a period of time, they will amass a collection of Pinewood Derby cars. My son already has four. Consider building some sort of stand to display the cars. Make sure you inscribe on the underside of each car the year they were built. You will be able to gauge progress in building skill and technique.

These derby cars are a fun project. Don't get too serious about it. Strive for fun! Who cares who wins the race. You are looking for an overall experience. The entire process is a great learning opportunity.

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Poplar Bookcase in an Hour

poplar diy bookcaseBookshelves in an Hour

This is a really fun project. How did I get the idea for it? It was a completely spontaneous thought. About five weeks ago, I was in Ft. Worth, Texas doing a television appearance. The public relations (PR) firm that hired me had scheduled a unique opportunity. A morning TV news show wanted me to be on the air for one and one-half hours doing a project. The plan was to introduce me at the top of the show and then cut back to me every 20 minutes or so to check on my progress. The PR guy thought it would be great if I built a window seat. I roared with laughter! That would take about 12 hours with a helper under perfect conditions!

Poplar Bookshelves Can Be Done in an Hour

This discussion took place while we were waiting at the airport luggage carousel. The TV appearance was to happen in less than 24 hours! After I stopped laughing, Jerry, the PR guy said, "Well, what else can we do?" I said, "Let me think about it as we drive to the hotel." I knew the project had to be simple and it had to pertain to what the viewers in Ft. Worth needed. They have no basements there, so space is at a premium. Bingo! A bookcase popped into my mind.

A Bookshelf Plan

Using a scrap piece of paper, I drew up the plan for the bookcase in about five minutes. Several thoughts drove the concept. I knew that the project had to be simple so that I could complete it in the allotted time while on TV. If I didn't finish it, then it would not be as simple as I said and my credibility would be challenged. The project also needed to be modular. This would save time and make it affordable. You probably can see now why I chose it to be 4 feet wide and 4 feet tall! To make a long story short, I completed it with about 6 minutes to spare and the TV hosts were amazed.

DIY Bookshelves in 90 Minutes

The key to success lies in making sure the pieces are cut square and that they are the exact lengths I prescribe. A 12 inch diameter power miter box is a perfect tool for this project.

Once all of the pieces are cut, start by attaching the top to the side legs. The top overlaps the legs. Use 4 nails at each end for this. Pre-drill the holes with a bit slightly smaller than the diameter of a nail. This will prevent splitting the top of the bookcase. Do not drill into the end grain of the side pieces.

The next step is to install the bottom shelf. It fits in between the two legs. It must be held up from the bottom edges of the legs so the toe kick board can fit below it. The bottom of the toe kick board MUST be flush with the sides. Failure to do this will cause major appearance problems!

Use Plywood to Make it Square

I like to square the bookcase up at this point. The easiest way to do this is by nailing on the plywood backing. Notice that one half inch is cut off the bottom of the plywood. This is done so that the legs support all of the bookcase weight. It also makes the bookcase more stable. Be sure you cut off the bottom of the plywood and not a side! Keep in mind that the backing looks best when the grain of the plywood is oriented up and down, not sideways. Once cut, place a factory edge of the plywood flush with the top of the bookcase. This task is simple if you lay the bookcase down on the floor. Place the best edges of the case facing down. Pay attention to what is at the top. The plywood should be flush with the sides or in just a tad. Sometimes, the plywood comes from the factory a hair over 48 inches. This is why the bookcase is actually 48 1/8 inches wide. Start nailing the top edge. Once this is complete, align one side so that the plywood is even or parallel with that side. Nail this side. I space the brass nails about 8 inches apart on the back. With one side and the top nailed, the bookcase will be squared automatically by the plywood. Nail the remaining edges at this time.

The top apron and toe kick boards are now put in place. Use two nails at each end to secure these boards. You are nearly complete!

The Finishing Touches

Cut the decorative molding to fit. The miter angles are simple 45 degrees. If you have 4d finish nails, use these to attach the molding. The 6d nails are a little too big for this.

The final step is to cut the shelf standards and then attach them. These can be easily cut with a hacksaw. Hold the standards in about 1 inch from the front and back edge. Pay attention when you cut them! Always cut from the same end or they will not work. Pay attention to the numbers on the standards to see what I mean.

This is all it takes, seriously. Once all of the wood is cut, the entire bookcase can be assembled by you in 1 hour or less. Be sure to use a nail set to countersink the nails. Sand it well before finishing it!

If you want the plans to build this wonderful bookcase simply click on Tim's Deluxe Bookcase.

poplar bookcase by tim carter

I built this in one hour using simple tools.

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AsktheBuilder mp3 Radio Show Aug 20 2005

Each title below is a direct link to a downloadable mp3 file. Just click the title if you want to listen. Right click if you want to download into your computer to save and play at a later date.

The Copyright to all radio segments is owned by Tim Carter. I would love to know what you think of these radio segments.  Do you like them? Do they help you? Have they saved you money and/or time?  Let me know by sending me an email: [email protected]


Custom Colored Pegboard Factory Tour

DIY Garage Door Installation

Cleaning Pet Stains off Hardwood Floors

Garage Roof Made From Concrete Leaks

How to Do Talk Radio

Installing Ceramic Tile Outdoors

Flooring Solution for Dogs

AsktheBuilder mp3 Radio Show Aug 13 2005

Each title below is a direct link to a downloadable mp3 file. Just click the title if you want to listen. Right click if you want to download into your computer to save and play at a later date.

The Copyright to all radio segments is owned by Tim Carter. I would love to know what you think of these radio segments.  Do you like them? Do they help you? Have they saved you money and/or time?  Let me know by sending me an email: [email protected]


Open - Stained and Stamped Concrete

Wireless Smoke Detectors

Restore/Rebuild Front Porch Stoop

Shower Seat Building Tips

Correcting Linear French Drain Mistakes

Extension Cords, Accessories & Storage Tips

Extension Cords

Voltage drop across electrical wires is really no different than water pressure loss in your water supply lines. The electrical current encounters friction as it tries to travel great distances. This friction reduces the energy level of the electrical current. Voltage drop doesn't hurt things like light bulbs. They just burn with less intensity. However, electrical motors react differently. To offset voltage drop you simply use large gauge wires that can deliver the required power at the end of the wire run.

Mr. Ohm and His Law

A scientist, who lived in the early 1800's named George Simon Ohm, discovered an interesting mathematical relationship concerning electricity. The formula he discovered is very simple. It simply states that if you multiply volts times amps you get watts. For example, say you have 120 volts and a motor that draws 15 amps while running. 1,800 watts are used while this motor spins.

So what does this have to do with voltage drop and extension cords? I'll cut to the chase. Mathematical formulas dictate that if you adjust one value on one side of the equation up or down, you have to adjust another value on the same side so that the total stays the same.

This means that if there is a voltage drop, the amperage must go up to compensate for the voltage loss. When the amperage goes up in an electrical motor, it can cause the wires in the motor winding to overheat. This in turn causes the insulation on those wires to melt which leads to motor failure.

So if you power your new circular saw, table saw, hedge trimmer, etc. with a wimpy extension cord, you may be causing damage to the motor windings.

Flexible Cords - A Reality!

Who among use hasn't cursed those wicked orange extension cords that will not coil neatly in our hands? Older homeowners remember extension cords that were supple. The outer insulation in these black beauties had high rubber content. The vulcanized rubber made them very resistant to chemicals and allowed the cords to flex with ease in the coldest temperatures.

The advent of cheap plastics 20 years ago lead to a flood of "safety" orange poly-vinyl chloride(PVC) insulated extension cords. Sure there were some advantages to using PVC (don't ask me what they are), but those never made up for the rat's nest of tangled wire one has when the temperature drops to 20 degrees!

Fortunately, you can still buy a super high quality rubber extension cord or two. The black cord has been replaced with a brilliant amphibian green color. It is both flexible and environmental!

Extension Cord Accessories

Have you ever plugged in an extension cord, walked 100 feet and then had no power? That can be aggravating. What if I told you that you could have a cord with a built-in light at the end of the cord? The light would glow when you have power.

How about a short extension cord that has a built in circuit breaker? Or one that has a built-in safety ground fault circuit interrupter (GFCI) breaker? This is what is now available in cords. Many of these features were not readily available four years ago - at least not to homeowners like you and me.

You can even buy an extension cord that powers different accessories like trouble lights. Instead of buying several different lights all with different cords, why not buy one cord and then plug in the lights and other accessories into the single high quality cord? The person who thought of that should get the rest of the week off!

Storage Tips for Cords

Do you have an extension cord that is twisted and distorted? It probably has been wrapped around your hand and elbow a few times. This will really mess up a PVC cord that contains filler fibers within the cord. The filler fibers are inserted to separate the wires and give it a more round appearance. They also bind and twist if you coil the cord improperly.

The best way to wrap up a cord is to use a method similar to the way a cowboy coils a lasso rope. You hold the cord in one hand and make successive loops . You need to twist the wire as you make the loops or it will start making figure 8's in your hand.

Another handy device is a cord rewinder or retractor. You can store an extension cord without twists if you wind it up on a factory made spool or one you make yourself. This is the same way the lawn chemical companies store their spray hoses.

Another simple method of storing an extension cord is to coil it within a 5 gallon drywall bucket. Be sure to remove the joint compound first or you will have a real mess on your hands! I know, make sure I don't quit my day job to become a comedian.

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Extension Cords Manufacturers and Features

Extension Cords Manufacturers and Features

I was asked to write this column by my editor at the Star-Tribune in Minneapolis, Minnesota. At the time, I felt that it would not be a problem obtaining information about something as simple as extension cords. Guess what? I was wrong!

There are probably many extension cord manufacturers. If so, it is tough to find them. I was only able to locate two! One of them happens to be the biggest player in the market place - General Cable Corporation. They make an unbelievable assortment of high quality extension cords and accessories. The astonishing thing is that they are located just 15 miles from my house and I never knew it. The other manufacturer is Leviton. Unfortunately, all I can give you is a phone number. I made repeated efforts to obtain information and product descriptions. Nothing was ever forwarded to me. I hope you have better luck than me!

  • General Cable Corporation
    800-382-4730
    From what I gather General Cable Corporation is the leader in the extension cord industry. Their cords are distributed nationally in virtually every hardware store chain or major home center. You should not have trouble finding them. The cords and accessories are OFTEN sold under the trademarks: CAROL, FROGHIDE, ULTRA FLEX and ROMEX.

    General Cable's cords are marketed in four categories:

    FrogHide - This is the best rubber cord you can buy. Its flexibility and durability is unmatched. The plug ends are molecularly bonded so the ends should not fall off! It has a distinctive green color so look for it where extension cords are sold. It sports a FULL LIFETIME WARRANTY - I've never seen another cord that offers this.

    Lighted Yellow - This is cord that has a blend of rubber and vinyls (I think...). Its flexibility is great at room temperature, but only so-so at low temperatures. It has a cool clear female end that glows when the cord is plugged into a working power source.

    All Weather Blue - This cord is made to be flexible at cold temperatures. Believe it or not, at room temperature it is unruly - I know as I own one! These cords are the exact opposite of the standard orange PVC cords that probably every homeowner has!

    Round Orange - This is the old standby orange PVC cord. It is flexible when the temperature is above 60 degrees or so. But when it gets cold, forget about coiling this one up!

    General Cable Corporation also makes the extension cords that have circuit breakers in the cord, ones that have safety GFCI circuit breakers within the cord, multiple head cords, extension cords that have interchangeable accessories, and other cord accessories. You absolutely must give them a call to find where you can purchase their products locally. You will not be disappointed, that I can assure you!

  • Leviton
    800-824-3005
    Leviton also makes extension cords. However, after repeated attempts, I was unable to get information. I hope that you can do better than me.

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3 Way Switch & 4 Way Switch

Nothing is more frustrating than trying to figure out why a 3 way or 4 way light switch system doesn't work. Years ago, I got a severe brain cramp one day trying to hook up two switches. After I consulted some books, it became crystal clear how to do it. Ever since that day, I have memorized the wiring diagram to successfully hook up 3 & 4 way switches.

***Click here for great wiring diagrams!***

How to Wire a 3 Way Switch Video

Multiple Possibilities

The electrical wiring in your house can be installed in several ways. This can cause problems when trying to diagnose a wiring problem with 3 way or 4 way switches. If you decide to tackle this easy problem, it will help you immensely if you buy a continuity tester. This is a simple battery powered device that tells you when a circuit is complete.

Continuity testers are often electronic devices that have a needle gauge or a digital readout. There are always two wires that lead from the tester with metal tips. If you touch the wires together the needle should jump to the end. This shows that the current from the battery is flowing from one wire through the other wire to the gauge. Here is why we need this great tool.

If you goof up the wiring of 3 way or 4 way switches, you will need to determine which wires go where. There are basically two types of wires we are concerned with: the common wires and the travelers. The continuity tester allows us to figure out which wire is which.

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Telephone Cable/Wire Installation Tips

Separate Holes

Avoid the temptation of running your telephone wires in the same holes as high voltage wiring. This is the first mistake I often see. This practice places the telephone wire parallel and in close proximity with the high voltage wiring. This in turn can lead to interference on the telephone wire. When electricity flows through the higher voltage wire, it can sometimes induce an electromagnetic field in the telephone wire.

Try to stay at least 16 to 24 inches away, if possible from high voltage wires. This can often only be accomplished by drilling a separate set of holes for the phone wires. Don't drill less than a 3/8 inch hole.

Wire Type / Size

Use UL approved twisted pair solid conductor wire. 22 or 24 gauge is preferred. I highly recommend that you use 6 conductor wire instead of 4 conductor. This means that 6 wires are bundled together inside the outer insulation. Why the need for the extra two? I like to have at least two separate phone possibilities available at each outlet with a spare pair in case of a wire failure. This can only be accomplished with 6 conductor wire.

Home Runs..... No, not like Baseball...!

A home run in wiring refers to a single cable that leads from a central junction point to an individual outlet location. It does this without stopping at any other outlet location on the way. Your phone cables should all be home runs. Most electricians run the cable in a series. In other words, they wire from the central phone location to and through each outlet location. This practice limits your ability to isolate trouble. It also doesn't let you turn off a phone in a separate room without penalizing other downstream phones.

Stripping Insulation

You should purchase the inexpensive special wire strippers for low voltage wiring. They do a great job. However, the hardest insulation to remove is the outer cable insulation which surrounds all the inner wires. You MUST carefully remove this without scoring or removing insulation from the inner wires. This can be tough to do. I remove the outer insulation by gently using only partial pressure on the wire stripper's largest setting. This allows you to partially cut through the insulation. While applying this pressure, I pull the stripper towards the end of the wire. The insulation then rips apart without scoring any of the inner wires.

Attaching Wires to Screws

Did you know there is a right and a wrong way to attach wires around screws? If you do it incorrectly, the wire will unwind as you tighten the screw. As you look at the screw head, always wrap the wire around the screw in a clockwise fashion. Do not wrap the wire around the shaft of the screw several turns. In fact, the wire only needs to wrap around the screw just a little less then one turn. Try to minimize the amount of insulation you remove from each individual wire as well. Exposed wires can touch one another when you jam them into the box when you screw the outlet to the box. If the wires touch, it can short out the connection.

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Telephone Wiring Tips

Telephone Wiring Tips

Installing telephone cable is really a treat, especially if you have been running 12 gauge high voltage cable all day. The telephone cable is easy to pull and work with. The only challenge I find is removing the outer insulation which covers and protects the individual wires within the cable. This is where most rookies get into trouble. We will talk about this in a few moments, so be patient.

Modems or Teenagers

The phone companies are being inundated for requests for additional phone lines in residences. The reasons vary, however in most cases it boils down to a computer modem or a teenager who needs a phone connection. Some houses have as many as three or four phone lines, especially those where a person works at home like me!

If you find yourself in this spot and wish to save some money, then I suggest you take care of installing the phone line once the phone company has installed the outside cable and junction device inside your home. Phone cables can be successfully installed by just about anyone.

Two Wires is All it Takes

Most people shy away from phone work because they see all of the multi colored wires at the phone outlet and at the junction box. Relax! Only two wires power your phone, fax machine, or modem. The phone cable that comes from the street into your house either has two wires or contains several pairs of wires. My house has an underground cable which I installed. It happens to contain five pairs of wires or 10 wires in all. As long as all the wires are good, this means I can have five separate phone lines feeding into my house.

Four Pair Minimum for Your Line

If you are getting ready to extend a new cable from your phone junction box or where the phone company installed/terminated your new line, you should use a minimum of 4 or 6 conductor cable. What's that? It is simply a single cable that contains 4 or 6 separate wires. Why waste the other two wires? Well, you may not waste them. You may install another phone at a later date, or, you may have to use one of the wires in case one of the other wires you intended to use is defective.

Older houses often contain 4 conductor "quad" cable. This cable often contains four wires which are solid in color. The wire colors are almost always red, green, yellow, and black. If you decide to use these wires, you will not obtain the highest quality voice or data signal.

Modern phone cable for residential houses contains individual wires that are 22 or 24 gauge in size, band striped for identification purposes, and arranged in twisted pairs. The twisting of the 2 wires around one another enables the quality of the signal to stay at a very high level.

Point A to Point B

Running cables in an existing house can be a challenge. Some people will leave phone wire exposed and run it along baseboard. Phone company installers did this for years. In fact, they had a nifty little staple gun that allowed them to neatly do this task. I would only do this as a last resort. Phone cable is somewhat fragile. It really could use as much protection as possible. Try to run it within walls when possible.

If you are trying to get a cable from one floor to another, or say from the attic to the basement in a ranch house, find the plumbing stack location. Often I have had great success in dropping a nail attached to a string from the attic to the basement right alongside a plumbing stack. The plumbers almost always cut the flooring or plates out with extra room to spare. If you jiggle the string, the nail drops right down into the basement.

Making a Test Outlet

A pair of alligator clips attached to wires that lead to the back of a modular outlet allows you to make a crude copy of those cool little phones you see the phone installer wear on their tool belts. This setup allows you to clip onto the ends of wires within your house or at the phone company termination block to see if you can generate a dial tone. This little setup can be made for less than $8 in most cases and allows you to use a standard phone to test your lines.

Make sure that the alligator clips do not touch one another when in use. If they touch, the line will short out and you will get nothing but static, disconnected, or both.

I like to make the leads on the alligator clips about 16 inches long. The wires leading from the ends of the alligator clips hook up to the green and red wires on the back of the modular outlet. These two wires are almost always traced to the center two wires or conductors of the modular outlets and mini plugs.

When not in use, store this outlet and the alligator clips in a self sealing clear plastic food freezer storage bag. The bag keeps it clean and you can always see the contents!

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