thanks for the pics dag-nabit. that pxl looks realy nice. how do you find the 3g to sharpen. havent had the need to sharpen my u2 yet but hopefully the dc4 can do the trick.
Two part answer.
1. I haven't needed to sharpen the FH9 yet, but I EDC a P/3G folder. I was getting frustrated trying to get a razor sharp edge back on the knife using a diamond/ceramic combo. In reality I was getting the knife plenty sharp for every day tasks, but not back to the factory edge.
The P/3G is convex ground, so I finally tried the mousepad/sandpaper method I had been reading about and my P/3G is back to razor sharp. (took about an hour to re-establish the convex, now I can freshen it up in 5 minutes or so)
The 3G steel takes extra time to sharpen, but isn't really any more difficult, just more time needed.
2. As for the FH9, with the flat, scandi grind with a bevel edge, the flat surface of the DC4 should work fine for sharpening. I will know more first time I try to sharpen it. It's possible I may find my technique just sucks.
With 3G, expect it to take a bit more time.
3. (OK it's a three part answer) The U2 is a convex grind with a bit of a bevel for the edge. You should be able to sharpen the flat bevel with the DC4, but if you find you are not satisfied with the results try the sandpaper/mousepad technique.
Kevin
Note: this is just my experience/observation, I have read a couple threads where members report excellent sharpening results on convex with stones or rods.