Summary

Made a handheld model of a Ballista for my Design Studio class. Designed to shoot a standard pencil if the eraser is chopped off and a notch filed in.

Instructions

Printed each part individually.
Holes drilled in the string pulley, crank, and ratchet. Screws were self tapped in to lock them to a metal bar. The support rods were then glued to the gusset plates, using standard super glue, and the main body was attached to the bottom gusset plate.
The Ratchet Prawl was attached with a 1/4" steel rod, same as the crank/pully assembly and the string holder/pull shoe. It was strung up with 25lb fishing line, ran through 4 times to quadruple the strength.

Handheld Torsion Crossbow