We had a salesman leave us couple of bottles a while back.
I had to make ten 2 1/2 inch diameter 8 TPI bolts for a large Rudder Palm from 17-4 PH at H1150, so I tried it. Threading with a insert tool at around 200 rpm, it worked fine.
But no better than the Sultex D that we buy by the drum, which works much better on mild steel. While it does clean up better than conventional oils, that is not a big consideration in our shop.
I am not sure how it will work on a reamer. I use the Dark Rigid for reaming chambers, but keep in mind, I do not ream chambers in the conventional manner.
We get samples of just about every consievable cutting oil and cutting fluid made. Most are geared toward the CNC world, because that is how the major machining industry has evolved. In a "niche" industry such as ours, we tend to stick with more conventional products that have worked well with our machining challenges.