Ballista

thingiverse

This miniature Roman ballista replica features a smaller size (non-exact) and is made of plastic instead of traditional materials. It can fire a pencil approximately two feet away with less force than a human throw. The working mechanism is explained below, along with a short video demonstration. Although it may be classified as a weapon by Thingiverse policy, the creator considers it a toy. Safety precautions are advised to avoid eye injuries. Future improvements include adding a mounting point and period-style ratchet, winch, and trigger mechanism. To assemble the ballista, print out all required parts: one of each body part (technically, "ladder"), two frames, and a pair of arms. Smooth the bore of the body parts if needed. Assemble by connecting the two body parts together, followed by attaching the frames around the matching insets of the body. Attach rubber bands to winders, then to arms, and finally to second winders. Position the arms correctly (refer to pictures) and wind up the winders with moderate tension. Secure a string to each arm end, passing through the slot in the body. Finally, pull back the arms' strings from the back hole of the body and tie a second piece of string to the middle of the first one, creating a knot for pencil holding. The ballista is now complete and ready to use.