Cantilever 2

Acrylic

Testing

 I made sure there was a consistent thickness throughout the whole of the cantilever, to make sure there were no specific weak points.

I did not focus so much on looks at this point...

The cantilever failed by shearing across the front section. As revealed by Dan, the laser cutting process heats and weakens the acrylic. The areas with lots of condensed cutting will be the weakest.






 Class comparison

The cantilever weighed 47 grams and supported 4600 grams of weight. This gave a ratio of 97.9. The weight, load carried and ratio were about average compared to the class.










Cardboard

Testing

 Similar to the first cardboard cantilever, I have gone for a corrugated cardboard technique. This one was laser cut from 1 mm cardboard, making it quite accurate compared to the first cantilever.

This time the corregations flowed horizontally as the load and pull on the cantilever runs horizontally.

As the first cantilever buckled along the front jig pole are, I have made this the thickest area with the most condensed corrugations.

In this photo you can see how a three plate system was used to maintain strength and allow the scale to be attached.

I also smeared a layer of hot glue across the outside of the cantilever to form a glue- cardboard hybrid, for strength.

 Failure

Like the first cardboard cantilever, it failed by buckling at the front jig pole. The only way I could strengthen this area is by adding two layers of corrugated cardboard...

Class comparison

With a weight of 136 grams and the ability to support 13600 grams, it has a strength to weight ration of 100. This scored a comfortable first place amongst the class, second place scoring 73.