What is the best Aluminum grade for my project?

[blakej]

Hi all, I'm looking for suggestions on selecting an Aluminum grade which fits the following criteria--

-The cheaper the better!
-Medium hard to very hard
-Highly machinable (I'd like to see chips, not strings.)
-Holds anodize well
-Strength is not particularly important

I have some ideas, but it's always nice to see some validation of those ideas without sharing exactly what they are. It'll boost my confidence that I made a good choice. Thanks in advance!

Blake

 

[Doug Huffman]

I believe bicycles are often 6061 or 7005.

 

[cjl]

If hardness isn't a huge priority, I'd look into something like 6061-T6. If you need high hardness though, I don't think you can get it without going to a fairly expensive, less machinable alloy (like 7075).