6061-T6 is an alloy that turns well as far as metalworking goes. It is a hard alloy, and has a strength that is nearly the same as mild steel. The high temper (T6) makes it turn easily without the problems associated with softer aluminum alloys. For turning on a wood lathe with gouges and srapers, the temper in it might make for slow turning. Not many grades of aluminum are commonly available in rounds. 2011-T3 and 2017-T4 and 2024-T4 are also grades that are supplied in rounds, but may be more difficult to find, and are harder than 6061 T6. 6061-T6 will cut clean without tearout and take a high polish.