I have always loved the American trucks and watched Convoy lots of times. This gave me the idea to design a toy truck, for kids to drive an play with. So here is how i did it. Have fun.
Step 1: Parts and Material
Fischertechnic parts (webshop: http://www.knobloch-gmbh.de/)
31003 x2 Gray piece
31061 x1 Connector piece
32880 x1 Black piece with hole (it's gray in my model)
35112 x1 Cogwheel
35113 x1 Cogwheel lock
38472 x1 Cog-beam for steering
35998 x2 Steering frame
31843 x2 Steering block
38246 x1 1x1-plate
37679 x4 Axle lock
35031 x10 Wheel rim (part1)
31058 x10 Wheel rim (part2)
31018 x10 Tire
31916 x1 Steering wheel
31915 x1 Steering wheel lock
(When you order, you might consider to order more wheels and rim-parts if you want to make a trailer to...)
You can download a complete parts list at www.knobloch-gmbh.de
14 or 15 mm plywood
3 mm plywood
ø15 mm round wood (for the exhaust pipe)
ø22 mm round wood (for the air condition filters)
ø28 mm round wood (for the gas tank)
Piano wire /steel beam ø4mm 1500 mm (for the axles and the steering beam)
Graupner universal joint ø4 or 4.5 mm
Graupner axle lock
250 mm bras or plastic tube ø5mm for the exhaust pipe
Step 2: Instruction Drawings
I have attached a PDF with the drawings of the parts, you need to cut out of 3 mm and 15 mm plywood. The drawing has one measurement on each page, so you can check with a ruler, if your print has the right size to match the wheels.
The cabin pieces are glued together edge to edge using a bunch of clamps.
I haven't made drawings for the exhaust pipe, air condition filter and tank. You just figure that part out your self as you go along - it's fairly easy and you can design it to your liking.
Step 3: The Cabin and Sleeper
Her comes a little apology: I had to reverse engineer this instructable. Therefor the truck on some of the pictures is painted though that normally would happen later in the process - I hope this isn't to confusing...
So, back to work...
When you have cut out all the pieces, it's time to glue together all the stuff. If you cut out the pieces fairly accurately, it should be pretty obvious what goes where. You glue the cabin pieces together edge to edge without any further screws or nails, therefor the edges have to be very accurate and straight otherwise the connection won't be strong enough. You might have to sand or plane the edges before gluing to ensure perfect fitting...
The wheel guards are made of a 0.5L soda bottle. You cut out the bottom round and then split the bottle in two pieces according to the dashed line. Then you glue and fix them with screws onto the hood. To do so, you need to glue a solid piece of wood inside the hood for the screws to dig into. This will also strengthen the whole cabin. Picture no. 2 shows the construction. You can also see an extra wood piece at the rear end of the cabin. That's for attaching the cabin to the wheelbase. This piece has to stick out a little bit to give it the right distance to the wheel base. You glue it onto the cabin just befor you assemble the whole thing. This way, you make sure, everything fits together and the wheels don't collide anywhere. I didn't make exact drawings of those parts, because the end result often turns out a little bit bigger or smaller, than expected. Therefor you have to take measure of the finished result and shape it very accurately - this will give the truck the best strenght...
Before you paint the hood. you might want to glue a folded piece of paper on top (the white bit on picture 4) to give the hood a bit more shape...
The sleeper works the same way... The exhaust pipe is made out of a 15 mm round piece of wood. I used a rough rasp to press a hole-pattern into the wood before painting.
Step 4: The Chassis
Before you fix the cabin and the sleeper to the chassis, you have to prepare it and put on the wheels and steering. Notice the square nobs on the steering frame bits: There is a nob on each side. You need to carve out a little hole in the chassis before you screw the steering on to it. This will stabilize the positioning of the whole bit. The two gray bits are not glued or screwed on to the chassis - I just make sure, the gap is a little bit tight - this allows you to fine tune the position so the steering goes smooth.
Important. Each front wheel use a 40 mm long ø4 mm axle. You use one of the Fischertechnic axle locks at one end of the axles. You might need to glue it on to the axle with cement glue, so it won't come off - driving is demanding on the materials. Picture 3 should make it clear, where the axle locks go...
Step 5: Assembling and Painting
Now you are ready to paint and then assemble all parts. The decoration is drawn in Illustrator and printed on a color printer, but you could use paint or photoshop as well... Also notice the handles and "lamps" which I made out of matches... The tank is made out of the 28 mm round wood, that i cut in half. Well there you are!
Step 6: Variations and Design
I noticed, that my kids enjoy the fact, that they have to push the steering to make the truck go - it makes them feel like thery are the engine themselves... Have fun.