Originally Posted by
dharmic
On the OD approach, even a zero rake should be ok because the material falls away from the centreline.
I'm not familiar with the lathe gauge you used but have you ensured the tool is flat as well as centred? With such a small relief and what looks like no rake at all on the top, if the top isn't flat with respect to the line from the centre through the cutting edge then yeah, it will rub.
Often the default angle set by the flats on the bar include a little kick for top relief - if that's happening then it would explain a lot.