I got bored one day in school so I took out some pens, scissors, and duct tape and did this in about an hour. This is the first crossbow I've seen that's collapsible.

Step 1: Materials

To build the crossbow, you need- Supplies- â¢3 Normal Disposable Pens with tubes â¢1 or more Pilot G2 ink cartridges (at least one empty) 1 is fine, the others are for ammo. â¢a couple of rubber bands- you only need one, but you need to see which one fits best. Tools- â¢Good Scissors (for cutting pen in half) â¢Hot Glue Gun (recommended)/Super Glue/Duct Tape â¢Small Scissors/Screwdriver/Drill (something to drill holes in the pen tube with)

Step 2: Cutting the Pens

So first you need to dismantle all of the disposable pens, and just keep the tubes. You can keep the ink cartridges if you want to use them as ammo later. You are going to cut one of them in half in the middle. Then, take the empty Pilot G2 cartridge and cut it off right under the yellow goo. It gets everywhere so don't cut the part with the goo.

Step 3: Making the Ammo Track

Take one of your pen tubes and cut it lengthwise down to about a centimeter from the end on both sides. SIDES not ends. Then cut away one side to open it to put in ammo.

Step 4: Drilling the Hole

You are going to take the third (base) disposable pen tube and drill a hole in it wide enough to fit the cut piece of G2 cartridge. It has to be tight enough to hold it in place, but loose enough to pull it out when you want to collapse it. You can use a drill, scissors, a screwdriver or something else sharp.

Step 5: Putting It Together

First, stick the cut piece of G2 cartridge into the hole on the base tube. Next, slide the halved pen tube pieces onto each side. Then, hot glue the ammo track down onto the base tube, about a centimeter from the end with the arms (cut tubes). The track has to be shorter then the tube, so trim it off a little so it has room on both ends. Also, before you move on to the next step, I suggest cutting some off the ends of the arms to make it look better and to make it easier to "string".

Step 6: The Bowstring

Now you're going to attach the rubber band. You need to put it around the two crossbow arms, either by taping it or cutting slits in the arms to hold it. If you have a long rubber band, it's better to tape it so it makes the band shorter and tighter. If you have a smaller band, you should cut slits/grooves on the ends parallel to the pen tube body to hold it, so it won't snap when you're cocking it.

Step 7: Collapsing and Finishing

To collapse, simply pull the half pen tubes off the cut G2 cartridge and pull the G2 out of the hole in the base tube to get a slim set of pieces that could fit in a glasses case. I hope you like your new crossbow! It works best if you use Pilot G2 cartridges for ammo, and Bic Round Stic disposable pens. This is my first instructable, so tell me what you think!