A few days ago (under the guise of the tailstock ram thread) I had a brief interchange with Lennie about the operation and setup of roller box tools in turret lathes.
Using his suggestions, I was able to rapidly diagnose what I was doing wrong with the one I had (which was basically *everything*) and had it set up properly in a half hour.
For those who care, I had ground the tool like a regular turning tool, with side clearance, front clearance, and side rake. Because I had never seen a box tool in operation before, I had it cutting on the *side* of the tool shank rather than the end. This worked because a) I had ground it like a regular tool, and b) I was running the spindle backwards.
It was a fiddly setup and took hours to get it to turn cleanly. The only way to set the diameter was by inching the tool in or out of the toolholder! ('this is crazy, how do they get the setups done in less than an hour with these damn things...')
The key to getting to run properly was lennies comment 'the grind on the end of the tool should almost look like the way the tool comes from the factory.' That and the statement that the spindle runs forward, not rev.
The tool geometry on those things is flipped - the chip comes off along the *end* of the tool. The closest thing I could liken it to is the diamond toolholder where the tool is held nearly vertically, at a tangent to the workpiece.
Only one grind on the tool is really needed, the toolholder sets all the other angles and reliefs. Crazy but as Lennie says, works just gangbusters when you get it setup right.
Thanks for taking the time to step a novice though the details, Lennie.
Jim