I have one of the SS mills, which I purchased in a lot of items from a nano brewery that failed to start due to COVID-19. I had seen the aforementioned videos on YouTube, so I did a quick inspection with a feeler gauge before buying it. The gap on mine isn't perfect, but it didn't seem problematic to me. I don't recall the specific difference, side-to-side, but visually, they look absolutely parallel when set at the default setting of "0" or 1.3 mm, which is a large default gap compared to standard home roller mills.
I don't think the knurls are a valid explanation. They're so widely spaced that it would be more likely than not that any measurement with a feeler gauge would land on ungrooved portions of both rollers.
I will, however, note that the milling action is quite different than a standard home roller mill. The fact that the rollers are so much larger in diameter and rotate at different speeds really does affect the way the grain is crushed. It's not just marketing BS. With mynold mill, I sometimes conditioned my malt with 1-2% water and the most notable change is how fluffy the grain becomes. The grain that took up 2.5 gallons of space before milling might take 3.5 gallons of space after milling. That's because so many husks remain intact, even though the endosperm is well-crushed. It's very similar in the SS mill
without conditioning. It is quite remarkable, IMHO.
SS Brewtech calls this "shearing action", but I'd describe it more like adding a rubbing action to the crushing process. This difference may account for the larger than normal default mill gap.
My main complaint about the mill may be a byproduct of that rubbing action -- static. I built an enclosed plywood cabinet on top of which sits the mill. When I've finished milling malts for a 5-gallon batch, I will be able to knock perhaps 2 cups of husks and flour from the underside of the top of the cabinet. I think an enclosed cabinet is essential for this mill.
People who drop $800 on a home malt mill are understandably expecting perfection and they're also likely to obsess over details like the alignment of the rollers. It was probably a mistake, at least from a marketing perspective, to fail to provide any means of adjusting the alignment.
I'm mostly happy with the mill because of the quality of the crush it produces. My wort has been extra clear and my sparges have run like clockwork since dialing in the crush which matches my set-up best, which is +1, or 1.46mm. Efficiency is good, too.
