Here are (will be) my go-to turning tools. All the inserts are Kennametal High Positive KC5010 grade. The triangular insert on the boring bar did a nice job initially on the toughish steel CTC use for their arbors but suffered from fine chatter when creeping up to the required finished size. Probably more to do with the bar extension and subsequent lack of rigidity than the insert. The insert in the tool in the QCTH did a great job today shaving off next to nothing while modifying my Chinese indicator stand.
I have not yet used the new Bulgarian. Friday's purchase to utilise the so far unused corners on my collection of broken inserts.
The Lefty is a CTC. Half the price of the Bulgarians and three times the finish.
BT