Boring five thou off the inside of schedule 40 pipe turned out to be the stubborn part of this build. The maker pushed through it on a Grizzly 0602 lathe spinning at 300rpm, and the first two carbide boring bars from Grizzly Industrial did not survive the attempt. The machine ran super hot, and the cutting left a brown heat ring on the outside wall of the pipe. That kind of heat with an internal cut is a real challenge, and the maker kept working the problem rather than abandoning the job.
The setup itself looks tidy. The hollow workpiece sits in a rotating spindle while the boring tool advances into the bore and cuts the inner wall. The bar is clamped in a tool post with black socket-head cap screws, which seems like a solid way to keep everything rigid at those speeds.
One detail worth noting is the feed rate. The maker tried both fast and slow settings while hunting for a cut that behaved, and the result was still two snapped tools before things clicked. In my view, that willingness to change one variable at a time is exactly the right habit.
The fix came from swapping to an oscarbide tool, and after that the needed results finally arrived. What stays open is the original question the maker asked: was the tool angle wrong, or was the tool quality simply poor?