"Bein' dis here is a triple-stringed, 2000 pound draw, double action windlass, siege crossbow..."
In "Men at Arms", the watch "raids" the Ankh-Morpork city armory. One of the weapons identified was a Windlass driven, triple-stringed, 2000 pound [draw] carriage mounted siege crossbow, loaded with large, blunt, steel-tipped bolts.

 


To make the siege crossbow as light as possible, I started with multiple sheets of Styrofoam insulation. These were assembled using a combination of hot glue and 3M spray-on contact cement. (Hot glue had a tendency to melt the Styrofoam at the high-temperature setting.) One sketch of a siege crossbow showed a "T" shaped extension out the rear of the crossbow. This would have doubled as a handle for pulling the bow, and for stabilizing the bow when on the ground.

Since I also needed some way for the troll to carry the weapon, I created a frame from PVC pipe that would create the end extension, and also reinforce the handle of the final crossbow. Sheets of trimmed foam were laid out around the tube on top of a solid sheet. All layers were then glued in place.

 


Short sections were cut to form a handle that would extend down from the central core of the bow. These were then glued in place around the pipe, and hot glue used to fill in the gap between the foam.

 

 

 

 

 

 


Heavy cardboard was cut into strips and hot glued around the ends. It would later be painted to appear to be steel reinforcement straps. (It did serve to reinforce the Styrofoam and prevent separation of the layers.

 

 

 

 

 

 


The bow itself is made from several layers of cardboard, hot glued together, then coated with several layers of marine epoxy. The silver color is from a combination of powdered graphite and aluminum mixed with the epoxy.

 


The windlass, or cranking mechanism was made with more PVC pipe. Toy gears were added to both sides, and linked with a small piece of dowel rod. When the crank handles are turned, all gears rotate, except the large cardboard one glued to the top of the bow.

 


Round metal studs were added to the cardboard strips to simulate rivets or bolts through the bands.

 

 


Once the main structure was complete, the entire bow was painted with a latex based sealer used for wallpaper preparation. This was followed with a layer of brown latex paint on the "wood" areas. Latex paint was used because a test of spray on enamel paint and liquid rubber attacked the Styrofoam, and were unsuitable for any type of finishing.

 


All exposed PVC pipe, plastic gears, and cardboard straps were painted with gloss black enamel model paint. Rust color paint was dabbed and streaked across the "metal" parts to age them.

 

 


Black water-based paint was dry brushed across the brown to create "wood grain" The "metal" bow pressure fits into a notch in the front of the structure

The "cocking" mechanism is based on one of Leonardo da Vinci's sketches. A silver-colored trigger bolt forces down the hook catch when struck with a hammer, releasing the basket assembly. The crank mechanism is used to move the whole trigger assembly forward and back along the track.

 


The screw is made from a dowel rod with split loom tubing over it, painted silver. The trigger mechanism is made from plastic printer parts and cardboard, and is spring loaded and functional. Two small screws hold the basket in place on the trigger block to prevent the basket from jarring loose. The bowstrings are made from black elastic shock cord, and allow a short amount of stretch without stressing the bow or other parts. This also prevents sagging of the triple strings over time.

 

 

 

 

 

 

 

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