This article of desktop weaponry accommodates multiple rounds of ammunition, launches exploding tipped cross-bow bolts, and slings wooden matches over 30 feet away. In this project we're turning some ordinary household items, into a surprisingly versatile, micro-crossbow.
Step 1: Watch the Video!
WARNING: The depictions of launching sparklers in this video are for demonstrational purposes only and are not intended to be duplicated. While this little contraption is micro-scale, it can still be dangerous to some degree. Use care and caution when choosing your ammunition, be aware of your surroundings, and never shoot at people or property. There may be risks associated with these projects that require experience, and/or adult supervision. Use of video content is at your own risk.
Step 2: Sticks and Templates
Start this project with a handful of popsicle sticks, and a template showing how to cut them.
You can get a free template and instructions here
Once the popsicle sticks are all marked, use something like a pair of gardening shears to cut the pieces to size without ever having to make a single measurement.
When all the pieces are cut, paint them completely black with a permanent marker.
The ink will probably take just a minute to dry, so now would be a good time to round up some metal hair clips.
Step 3: Limbs and Support
You'll only need 2 of them, and with a little manipulation, the inside clip will break off cleanly at the bottom.
The first step of assembly is securing the clips to the wooden supports with a bit of hot glue, so that when it cools, the limbs arch away from each other in a bow shape.
Next, go ahead and add some hot glue to the inside of the arch and press the second support firmly into place.
I cleaned up the excess glue with a utility knife to get the look you see here.
The next part focuses on making the pistol grip.
Step 4: Pistol Grip
The outer rail needs just enough hot glue to secure the smaller, "rail spacer" flush with the tip.
I dropped the top down a touch, to form a little groove about half a matchstick deep, and it's important this flight channel stays clean, so ensure any excess glue gets removed.
Attach the handle support right behind the spacer, then glue the last rail in place.
I left a matchstick in the flight channel to ensure I got the spacing right.
To finish the frame, glue the "pistol grip" panels so they overhang slightly at the back.
You'll need to cut a very shallow groove for catching the bowstring, so try using a knife to carefully whittle out a small catch in the upper rails, in-line with the front of the pistol grip. While you're at it, use a bit of sand paper to lightly round the edges of the barrel to help prevent the bowstring from fraying and breaking. Don't worry about messing up the paint job … it's super easy to touch up make good as new.
Now, the crossbow starts to come together as the tip of the gun rails are pressed firmly into a dab of hot glue on the inside of the bow.
About 30 seconds of steady pressure works well to keep the connection strong as the glue begins to cool.
I chose to glue some fillets on the side for added support and durability.
You should also be able to see the flight groove is slightly higher than the limb supports. Now, when a matchstick's placed in the channel, it will hopefully slide freely and without restriction.
Step 5: Bow String
It's time to pick out a bow-string. I used embroidery floss from the craft section of a local super-center and I chose yellow.
Wrap the support at the bases of the limbs 8-10 times on each side. This will reinforce the connections exponentially, and a small dab of hot glue should keep the string from unravelling.
Next, push one end of the floss through the hole in the tip of the hair clip, tie it in place with a double knot, and add a bit of hot glue as well.
Twist the string around a few times to keep it tight, then flex the hair clips a little before synching down another double knot. This will keep tension on the string and increase the draw weight of the bow.
Add some glue to this knot as well, and trim off the excess thread to complete the basic crossbow.
If you don't have access to embroidery floss, try twisting about 4 strands of dental floss instead. It works great, and it's slippery enough to cock and fire a bolt that's already set in place.
Step 6: Trying It Out, and Making Some Upgrades
Occasionally the string will jump the bolt, and fail to launch. So use some pieces from the scrap pile, and glue them to the back to create a makeshift "retention spring". It'll fire the bolt every time.
The finger holds the bolt so securely, that it can be fired from any angle, even upside down.
I went ahead and wrapped the handle with yellow thread, and added a couple of mini-clips for additional ammo.
These "side-mount" quivers are simply made from a plastic drinking straw.
I cut two small pieces from off the straw, capped one end with some hot glue, and attached them to the side of the barrel at a bit of an angle.
Now when the bolts are inserted, there's plenty of tension to hold them in place, even if the crossbow's completely inverted.
Step 7: The Next Level
Take it to the next level with some contact explosive bolt heads.
I made these ones by securing individual snappers, to the tips of the sticks with a bit of electrical tape.
This is super awesome because now the bolts make a bang when they impact a hard target. Of course this should only be done outdoors and with adult supervision.