The Maker Racer MK4 was the first race car kit sold by GoTime (the prior versions were developed but never sold.) It was originally produced using publicly available 2D laser cutters and 3D printers. Now, you can download and build a Maker Racer MK4 as a maker challenge!
Step 1: Download and Print Out the Required Parts
There are 3 files that are needed to produce these parts:
- 1 file for plastic 3D printed fixtures
- 1 file for the cardboard / wood car body and wheels
- 1 file for cutting axel rods
Download these files from the site by clicking here.
Download and print out / laser cut the required parts.
You will also need to acquire a lanyard. You can get these from office / conference name tags or by buying them from amazon.
Step 2: Add Wheel Hubs
There are eight wheel hub parts used in this kit. You can tell the difference between wheel hubs and wheel bearings by looking at the surface of the center hole. The hubs have four nubs that point inward while the bearings are smooth. Make sure that you use hubs in this step and not bearings or your car will not work correctly.
For each wheel (x4), take one wheel hub piece and insert it into the square hole as shown in the picture.
Step 3: Complete the Wheel Hubs
You should have four wheels (each with one hub part inserted into them) from the last step. Now, take an additional hub part and press it onto the wheel's square hole from the opposite direction. The two hub parts should snap together. Do this for each wheel. You should now have 4 wheels that each contain a pair of hub parts which have been snapped together.
Next, take a wooden axle and press it into the hub of two of the wheels. The axle should fit snuggly into the hub. Make sure that the axle extends outward from the rough side of the wheel and not (much) from the finished or colored side of the wheel.
Step 4: Snap the Bearings Into the Car Bodies
Find the two car body parts and 8 bearing parts. Using the same technique shown in last two steps, place two bearing parts into each square hole (in the body) and press the parts together until they snap in place.
Step 5: Add Two Wheels to One Body Part
Take the two wheels that have wooden axles inserted into them and push the axles through the bearings in one of the car parts. The wheels should rest against the white side of the car part and the wooden axle should poke through the bearing by over an inch.
Step 6: Press Two Reel Parts Onto the Back Axle
Find the two reel parts. One should look like a top hat and the other should look like a plastic coin with a long nub on one side. In the picture above, the 'top hat' part is situated under the 'coin'. Press the 'top hat' part on rear axle and press it on until it almost touches that car body part. Be carful, if this part touches that car body, the axle will not spin freely. Next, press the 'coin' part onto the rear axle and push it down until it rests snuggly against the 'top hat'.
Step 7: Place the Second Body Part on the Axles
Find the second car body part and place it on the axles so that the axles poke through the bearings in the second car body part. The second car body part should be oriented in the same way as the first.
Step 8: Add the Last Two Wheels
Press the last two wheels onto the axles so that the white surface faces away from the body. The wooden axle should only be pushed through the hubs until a firm bond is made. It should not poke out very far. At this point, your car should start to look like a car.
Step 9: Add the Spacer Clips to the Car Bodies
There are numerous little notches cut into the body of the car. The clips should fit snuggly into these notches. Place each clip into a pair of notches so that the clip hold the two car body parts apart. Four or five clips should be enough to firmly hold the two parts apart while still allowing the wheels to turn.
Step 10: Add the Lanyard
Clip the lanyard onto one of the clips. It's best if the selected clip is towards the back of the car. Make sure that the string points towards the rear axle.
Step 11: Attach the String to the Rear Axle
This part is a little tricky. Pull the string out of the lanyard a little and then hook the metal loop (which is attached to the string) around the nub on the 'coin' shaped reel part. The string should run over the back axle, not under it. Make sure to hold the wheels so that the string does not pull off the coin immediately.
To Race: Place the car on the ground and gently pull it back. If the lanyard is correctly hooked to the rear axle, the backward motion should cause the string to be pulled out of the lanyard and wrap around the axle. When you let go of the car, the string should snap back into the lanyard and shoot the car across the floor!
Step 12: Done!
You are now ready to race!