Those are looking much better indeed :twothumbs
How much and how fast were you feeding the cutter radially (x) and then across the surface (y)?
Did you do only one pass, or did you reverse the spindle and repeated the cut?
My setup at this point goes as follows:
1. Make sure everything is concentric and the bar/tube is indicating nice
check that the knurler is centered perfectly by using a center in the tail stock. The tool is cut a 60 angle on the end of it as you can see in the pic below so you just make sure the center in the tailstock is fitting in the v perfectly:
2. The next step is key: adjust the cutters so they cut 1/3 of the width of the knurl wheel to set the depth. It works out about half the pitch of the knurl. I will have to measure it but this seems to be optimum. This is the "depth" of the "X" i.e. adjust till you get 1/3 width of the knurl making an impression. I also try to make sure they are sitting at mirror angles as this tool doesnt' have gears to keep them at the same opposite angles.
3. Fine tune the cutters so they engage at the same time. At this point, I loosen the two screws holding the angled rods the knurls sit on and adjust them so that when I turn the chuck by hand, they engage at the same time.
4. Feeding:
I played around with different feed speeds and the ones in the pic were at .0139 according to the table on the lathe. You can get different diamonds by speeding it up or slowing it down but with the larger knurls it seems to dig in and track so you don't get double tracking and you can control the shape of the diamond this way. With the 30 diametral pitch the tool came with, it is really finicky. I got some plain 20 tpi and 12 tpi knurls from enco and am getting much better results. FYI, these are plain 3/4x1/4x1/4 straight knurls with circular pitch and listed under "form knurls". The main thing is they are sharp edged and not rounded on the edges. The larger teeth seem to track better regardless of the diameter of the piece and I like the look of the larger knurls. The stock knurls are almost too small and it is so small you can't see it properly without a macro.
5. Keep the wheels clean while cutting: I found that by using compressed air and wd40 in alternating blasts on the knurls while it was cutting, I got much cleaner cuts because the wheels were kept clean.
I have repeatedly cut to get to this point using up 10 feet worth of 2" round bar and the larger knurls are finally giving me repeatable results regardless of diameter.
In answer to to your final point, everything was done in a single pass. You don't want to make multiple passes with a cut knurler. I tried it and the screws on the knurls tended to unravel as they are left hand thread and the cutter would bind.
Here is one final shot with better light:
