Small K'nex Crossbow

This a small K'nex crossbow, I made after my brother made a much, much bigger one.

Here is a quick YouTube video I made of the crossbow.

This one uses eight 4" long rubber bands. It shoots a ping-pong ball about 30 feet far.

One piece you really need is one Big Ball Factory Tubing. Otherwise it may not

shoot as far.

Here is how to build the crossbow, just build it exactly as instructed.

This a simple barn shaped piece that will be used to elevate the whole crossbow. You will need to make two of these.

On one of them you add these pieces.

Now attach them. This is the finished part that elevates the whole crossbow.

Now for the lower rail. To construct that you start off by building this. (Note: both sides are the same.)

Now build these two upside down "U" pieces.

Next, you need to build two of these "W" pieces.

Now for the upper rail and again both sides are the same.

This is eight blue rods long and each ends in a yellow connector.

Attach the "W" pieces first and then the "U" pieces to the lower rail.

Attach the upper rail on the top part. Now you are done the upper and lower rail.

This is the bottom part of the "limbs", you have to make two of these.

This is the top part of the "limbs" and again you have to build two of these.

When you attach the top and bottom "limbs" together, you need to add spacers and wheels on the ENDS of the triangles in this order: Big spacer, small spacer, wheel without tire, small spacer, big spacer.

Now add the "limbs" to the rails and this creates the arrow shape.

As I said in the intro, you need eight 4" long rubber bands.Join the rubber bands as you see in the picture and slide in the orange connector in the middle rubber band.

Stretch the rubber bands as you see in the pictures.

Make sure the orange connector is in the middle of the rails like this.

Remember to attach the two green pegs that are shown in: Upper and Lower rail. Pt. 1. to the gray connectors shown in: Elevation Help piece. Pt 2.

To launch, you will need a ping-pong ball. Place the ball so that it rolls down the rails, then grab the rubber band knots closest to the orange connector and pull back. 3-2-1 Fire!