Hello! Today I will show you how to make a sweet crossbow.

Step 1: Parts

For this Instructable, you will need:

A rubber band
Crossbow .stl files (you can download them from the next step)

3D printer or an account with a 3D printing service
PLA filament (only if you have a 3D printer)
Some kind of Slicer software (only if you have a 3D printer)

Step 2: The Files

These files were designed by Thingiverse user "senns", not by me. Here's a link to his user page:

http://www.thingiverse.com/senns/about .

However, I did make a couple of adjustments to the files while slicing them. The g-code file includes the arrow and ballista and is ready for printing, but if you would like to mess with the original files before printing, they are attached as well. The g code file is also 60% the size of the original model, just saying.

These steps are for fi you use the original .stl files:

***ONLY FOLLOW THESE STEPS IF YOU HAVE A 3D PRINTER

Upload these files into your slicer and slice them. After that, export the g-code to whatever folder you use for you g code files. If you want a mini crossbow, scale the files down to 60% size. The scaled down files take about 4.5 hours to print. Keep that print time in mind when scaling the files up or down. Load the new g code files into your 3D printer (I use a PRUSA is MK2, so I just put the files onto a SD card, but if you have a wireless printer, just upload the files wirelessly). Start the print and you are done.

****STEPS FOR SOMEONE WHO DOES NOT HAVE A 3D PRINTER

Choose the printing service you want to use. I recommend that you use 3D hubs, since their file sharing system is very easy to use. Upload the files and chose the hub you want to use. The hubs also give you the option of filament you want to use. Most filaments would be fine for this project, just use common sense when choosing. For example, printing this crossbow in a super flexible filament would not be that great of an idea, since the functionality of a crossbow is based on having a tense frame. The site will guide you through payment and the hub will give you an estimated delivery date as well.

Step 3: Adding the "string"

This is really straightforward. Just wrap the rubber band around the two posts at the end of the arms of the bow. Make sure the rubber band goes behind the firing mechanism as shown in the image. You now have a fully functioning crossbow!

I've gotten the mini version to shoot anywhere from 10-20 feet in this configuration. Having thin string in the place of the rubber band would allow the bow to shoot farther, but said string would also wear out much after than the rubber band. Experiment with different materials for a drawstring to see how it effects the firing range of the bow.

Here's a fun project with this crossbow: https://www.instructables.com/id/How-to-Make-a-Crossbow-Gauntlet/