Well, it may sound silly but all Ive turned in my Leadwell LTC-15 is stainless steel and tool steels with moderate tolerances (.005). I havent done any 6061 aluminum yet, and I am wondering what kind of tooling I should use. I was told to use High Speed Steel to turn it, for a nicer finish. The part im making has a .0004 tolerance, so I could use some help as far as speeds and feeds go as well. Like I said before, no experience on this type of material, let alone with such a small tolerance. Am I headed in the right direction with the HSS on this or not? Anything to set me straight would be appreciated. Thanks.

You can use uncoated carbide and it is possible to get inserts with a grind specially for getting a good finish on aluminum.

Your tolerance is tight for aluminum. Linear expansion per unit length per Deg F. for aluminum is 0.000012 so you really need a temperature specified for doing the measurement.

I use CCDT and DCGT syle inserts (uncoated carbide). They work extremely well on aluminium (and for the odd short run stainless job). They are designed to "scoop" the material.

regards

I use solid carbide positive rake inserts. They are made for aluminum. Aluminum is soft and a non-sharp tool tends to push it rather than really cut it, and chip control can be a PITA, but the positive inserts help.