I wrote a review of a KitchenAid ProLine Grinder a few days back.
In it, I pointed out that while billed as a near commercial level grinder, it was unable to grind fine enough to make espresso in my Rancilio Silvia. I recently cleaned and re-calibrated the unit, and a selecting 5.5 on the 1-8 setting dial delivered chunky, uneven pieces, perhaps suitable for a French press.
I blamed the burrs, which in my opinion were not sharp. They seemed to be made of a soft metal that did not keep the edge. I ordered a replacement set and comparison of the two burrs will come up in a future entry.
Anyway, after further fiddling, I found I could create a decent DRIP coffee grind at about 6.5 out of 8. This made a nice drip cup and worked well in a Kurig as well. But the point is made: If I have to dial it to 6.5 out of 8 to get a grind fine enough to just make a decent drip coffee, there is no way this device can put out a fine espresso grind, new burrs or not.
I will prove myself right or wrong in a future entry when I install the new burrs. Meanwhile, the KitchenAid ProLine Grinder is more of a wood chipper than a coffee grinder.