Turning aluminium with carbide, testing and chipbreaking...

[m_c]

The biggest issue with taking such big cuts with aluminium, is more speed than the amount of force required, so just keep an eye that things aren't heating up too much, and the headstock oil is clean and topped up.

PCD is for tough materials and/or where long term tolerance needs to be held i.e. on CNC machines that are expected to churn out thousands of parts while unattended. On anything else, it's pretty much a waste of money with minimal benefits.

[Peter Griffin]

I find polished inserts the best ( I get them from where I work) also the faster the spindle speed the better. The "birds nest" could also be down to the grade of Aluminium that you use.Again I get bar ends from work, we use FC1 and it chips beautifully. I also find a light spray of WD40 helps with cutting and finish.