Project #2: Well Windlass

Challenge: build a model of a windlass for a well.

-Well is 12 cm in diameter (12 cm gap between two tables) so device must span more than 12 cm.

-Available material: Delrin sheets and rod, 120 cm of string

-Device should be strong enough to withstand weight of bucket (a full 1 liter bottle of soda).

-The top 10 cm of the bottle should be lifted above the plane of the tables.

-Limited to 500 cm^2 of delrin sheet (1/8" or 3/16") and 50 cm of Delrin rod.

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My partner, Julia, and I had to brainstorm separately due to the snowstorm, but interestingly, our designs/sketches were a bit similar.

Julia's Sketches

My Sketches

We didn't have a formal Pugh chart, but we did compare different parts and determined the better alternative. We agreed that using 3 rods for our spool was better than using 1 rod because a single rod was too weak. We also agreed on having supports for the sides (rectangular sides) to make sure our device would be strong enough to lift the bottle of soda. Lastly, we decided to prioritize functionality (versus appearance).  

After brainstorming and deciding on a combination of various designs, we created a model of our well windlass using foam boards. We were satisfied with the model, so we began sketching on Solidworks.

One big challenge (and lesson learned from my first project) was determining the sizes of openings and holes.  We realized that the laser cutter cut a bit more than the dimensions on Solidworks, so we created several notches and pegs tests to determine what was tight-fit, loose-fit, and "middle-fit". Using the caliper, we decided the holes should be about 0.02-0.03 cm smaller on Solidworks (The laser cutter always cut more than what was shown on Solidworks). 

One new part of this project was creating an assembly on Solidworks. After we finished our sketches of all the parts, we created an assembly drawing using mates. Julia and I first had trouble mating all the necessary parts, but when we tried to do them slowly step-by-step, all the mates worked. 

Our Assembly Drawing on Solidworks

After we had the parts using the laser cutter, we assembled them using the drill press, hammer, and metal file.   We used 1/16" piano wires to make sure the device was sturdy and strong. We used the hammer to pound the short pieces of piano wires into the holes created by the drill press. The metal file was used to make the holes (for the Delrin rods) bigger because the holes were too small (we could have made them bigger on Solidworks). 

Parts labeled with tape (tape also used to cover sharp piano wires that we tried to file)

Julia using the hammer

Our Well Windlass

This project took a lot of time and effort, but seeing our well windlass work was exciting and rewarding!

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Update:
We figured out that our simple design used about 382.72 cm^3 of Delrin. Our design was simple and probably not the most visually appealing, but it used less than 500 cm^3 of Delrin, and it worked!