Built the main structure of the crossbow using the laser printer found in the lab where I made holes to hold the 2 axis of the track. The first hole was 2.5cm in diameter to hold the DC motor and the second hole was 1.5cm in diameter to hold a ball bearing where a 1cm axis would be fit inside it. Also cut using the laser printer, a 25 by 4cm wood that would be just above the track with a 0.5 cm by 20cm slit located in the middle which will allow the hook to pull back on the string. This will also have the arrow sitting on top of it ready to be launched.