Given Jason's experience in sharpening, I wanted to double-check my own experiences with the King 1200, as it had been a long time since I'd actually put M390 to it. I wanted to make sure my memories had not been contorted over time.
The knife is the Benchmade 581 Barrage in M390 at 60-62 rockwell
The stones are the King 1200, King 6000, and a suede leather strop with standard green compound at ~.5 microns.
Total time from wholly unable to cut printer paper to push-cutting with and against the grain on phonebook paper was 20-25 minutes
The glazing Jason mentions does happen if, like me, you prefer a very light touch in sharpening. However, upon the use of some pressure, though not nearly so much as to be uncomfortable, the stone worked the M390 quite well, building up a decent bit of swarf.
When I noted the glazing with a feather-light touch, there was some burnishing present, giving the edge a higher-than-1k appearance. Concerned for this, I checked the edge after the above work and, with the heavier strokes, saw the 1200 yield a finish in line with the grit rating. The picture is crappy, and is only meant to show the absence of the sheen the burnished edge had:
Notice the matte grey finish.
Higher pressure strokes (though, again,
considerable pressure is not required, only a comfortable moderate pressure) allowed the surface to refresh itself even against the M390. Notice in this picture the sandblasted finish of the stone as opposed to the slicker, smoother look a glazed surface offers:
After gently deburring on the stone, and cleaning the edge with one single light pass (on each side of the edge) on the strop, the edge whispered through phonebook paper.
Then it was time for the King 6k, which I personally felt did not feel any different. The stone has always felt incredibly hard and slick, no matter what steel I hit it with. The stone generates no mud, only swarf. On this stone, I used moderate pressure in the beginning and faded out to my standard light pressure by the end. I then flushed the stone's surface, deburred, and stropped on the leather for a total of 30 strokes. I personally did not encounter any difficulties with the burr on either stone. After the 6k, the blade was effortlessly push-cutting phonebook paper with and against the grain.
One of the issues Jason mentioned was a lower-than-typical polish, so I wanted to compare a few edges:
Above is the 581 Barrage
Above is the 300 Axis in 154CM
Above is the Kizer Vanguard Sovereign in VG-10. As you may be able to tell, this edge is the most highly polished, but it has undergone more stropping than the other two. However, none of the edges differ greatly despite all coming off the King 6000 and hitting the chromium oxide compound for some stropping.
Although the King stones are far from the best, I do think they sometimes have an
overly negative reputation. Personally, my King 1k and 1200 have been used successfully on M4 (62-64HRC), M390 (60-62HRC), CTS-204P, CTS-XHP, and numerous examples of S30V and S35VN. What they have not seen are the ultra-max steels like S90-110, Maxamet, 10V, 121 REX, etc, so I will withhold my opinion on them.
So I have affirmed what I originally stated:
Kings will work, but others will work better. Higher density aluminum oxide abrasives like Naniwa Pro will work faster and with
less pressure, and diamond plates will work with the
least amount of pressure, although I wouldn't say they're noticeably faster lest you risk scraping the diamonds off the plate.
You asked if you should upgrade, though: I say buy as diverse a sharpening arsenal as your wallet will permit. Kings are plenty adequate for non-supersteels in particular, Naniwa Pro stones are the ultimate in waterstones, diamond plates will be
optimal for ultrasteels (and the reigning gods of reprofiling, in my opinion), Norton Crystolon is an incredible value (and basically the only oilstone I think is worth a damn), et cetera, et cetera. With more diversity, you will be able to have a best-for-use option which will save you time and effort; as you saw, it took me 20ish minutes to resharpen the 581, whereas I would typically expect that job to take me about 10-15 minutes.
