[TalonDJ]

That number is probably the alloy of aluminum. I don't know the aluminum numbers well. The stuff around 2018 is a normal decently strong grade of aluminum. Can't say much else about it. We did not spend much time on aluminum in materials class. I had to check my old text book toe be sure that was an alloy number. I could be wrong if they are using some dimension number that is close to a normal AL alloy but I don't know of a unit of measure they that makes sense with that number.

[Mr. K]

Can anyone tell me what a hobbit is? and why this 'hole'?