Single point cutting at 60 degree compound.

[Mitch Alsup]

I believe that it does cut to one side to help ease the cut of the thread forming tool. Some will just go straight into thread with the cross slide on smaller threads. Also for my lathe the compound is set for 29.5 degrees, yours maybe different. I am still a newbie to machining as well.

Using one side to perform the cut is stiffer than using both sides, and thereby creates less chatter.

However, going in at a 30º (or 29.5º) cause the trailing edge of the tool to burnish that edge which will be "taking" the stress of tightening a nut. This leads to more reliable torque readings on the TW of the thread after being cut.