Milling aluminum??

[Karch]

WD40 the heck out of the bit while you work too. Aluminum gets gummy when it's being milled. The WD40 will cause the metal to sling off the bit while it turns. Use this pretty much whever working with aluminum. Drilling, sawing, milling. No need on a lathe. Do not use WD40 when messing with anything other than aluminum. It will not work with steel.

I worked at an aerospace machine shop for a few years, and I agree.
Tap Magic is also a great product, but WD40 gets the job done for less coin.