Capuchin Monk wrote:I think those grooves are for grabbing the beans to force them in so that they don't "dance around" at the top.

They may be for that purpose as well as cutting/grinding the beans. I've thought about how a mill with perfectly smooth cylinders would act on coffee beans, and it seems their action would be crushing rather than actually grinding, which raises in my mind concerns about the shape (in 3-D) of the crushed beans that emerge after being squeezed through each milling stage. I think they would tend to be splayed out rather than spheroidal, making "uniformity" problematic. Cylinders with actual cutting edges would not present such problems, which is why I tend to believe "roller mill" coffee grinders would NOT is smooth rollers. I could be mistaken, but so far I doubt it.

ira wrote: They were more of a sine wave surface with no sharp edges and no feeding towards the center, just perfectly straight. Maybe being 6 feet long makes the coffee running off the edges less of a problem. They were also 12" or 18" in diameter so a bit different scale. This is not a comment on how this grinder will work as I'm as excited as anyone that it's being done, but given how different it looks from the traditional roller mills I've seen, I wonder how similar it will be in it's results.

And trying to interest the people who make giant ones in making a small one always led to lectures on why it's not reasonable.

I'm trying a slightly different design. Still three sets of rolls, the upper most(feed regulated) is going to be completely straight as a pre breaker, then the last two sets will be sine wave like, but non chevron pattern. The tolerances have to be tight for it to work at all, so we will see. This shows two versions, single sided bearings, and a dual sided one


It's a complete guess as to most of this, I even used my large sockets as O.D. test with some coffee as to where to start. at least it will be fun, as I haven't really played with coffee things lately, and this will be a challenge.