orduek wrote:lpranal,
do you still use the grinder without the spring?

Yes, working fine with no spring so far. I might put it back this weekend and see what (if any) difference it makes

I received mine about a week ago.

I think it's a solidly built product, especially for the price. I like the ergonomics quite a bit, except for the catch cup, which tends to make a mess when dosing into a portafilter. An angled spout would have helped with this problem. Others have mentioned the static issue which is greatly mitigated by the addition of a drop or two of water before grinding, something I've never really needed to do before. I don't think rust will be an issue with this small amount of water. It takes roughly half the number of turns to grind the same amount of coffee compared to my home-built 38mm conical grinder.
So far I've tried it with pourover and with a Europiccola, both stepless and stepped. I prefer stepped for two reasons: the stepless adjustment tends to wander, and I like the repeatability of stepped adjustment. Set at 15 for pourover, there is a visible layer of mud on top of the grounds after brewing. I think with time the amount of fines produced will decrease, though. New burrs always need some breaking in.

With the Europiccola, as others have experienced trying to grind for espresso, the burrs have to be adjusted down until they are pressing against each other with some force which is somewhat worrying. I have achieved best results so far at setting 0. The grinder cannot be adjusted fine enough to choke this machine, unfortunately.

How is everyone indexing their grinder? The instructions have it indexed such that the number facing you when the handle is at its lowest position is the grind setting, so the numbers above correlate accordingly. But I find it more intuitive to index relative to the wiper position which points to 3 o'clock when the handle is at its lowest.

Also, I was not able to remove the upper burr. After removing the grub screws which hold it in place, I got the burr to wiggle a bit, but it could not be pulled out. Is there a trick I'm missing?

Put the spring back in and didn't notice any difference, so I'll be leaving it in. Doesn't seem to affect stability of the burrs. Definitely able to choke the machine now without needing to grind at the finest settings, so I'm happy with my purchase. Given how crucial the burr alignment procedure seems to be for making good espresso, I imagine I'll probably have to re-align every few months or so

Some many years ago we were promoting the Kyocera CM45 (Hario Mini/Porlex) hand grinders for use in espresso grinding...there are still videos out there of me using these grinders with commercial lever machines. One aspect of analysis of the grinder was the ability to "choke" a machine and yes, the grinders can choke a machine, and this was promoted as a good thing and an indication of the quality and desireability of the grinder.
We also promoted the Bacchi stovetop espresso machine and one customer who had both the Bacchi and an array of the small
Japanese ceramic burr grinders did a very thorough and rigorous study of using these grinders for espresso via his traveling Bacchi and his home prosumer machine and he was good enough to share his findings in relation to the concept of choking. He very convincingly demonstrated to me that yes, the grinders can choke the machines, but the machines were choking on fines. Flow rates in extraction can and should be controlled by the predominant target particle size and the ability to choke a machine may not be the best criteria for grinder or burr evaluation.
Please accept this comment for what it is: Simply the desire to move the conversation away from the concept of choking a machine as a relevant test for espresso grinding adequacy. No more, no less.

They advertise the grinder as a "$600 grinder performance for a third of the price." They promised they grinder would operate on Turkish - French press range! Could you tell they've fulfilled the promise if people weren't able grind fine enough to choke a pump driven machine?

+eleventy for the "choking a machine" concept as irrelevant... that in/ability could easily be fixed by shims anyway; the important issue IMHO is consistency and fines as OE quite ably noted. Thanks.

Strange thing is, most people here are trying to use it for espresso

I don't know why you would consider that strange. The fact is that the ROK grinder does a nice job in the espresso range & the beans/blends that I've run through it have produced some very tasty shots on my machines. The shots have come surprisingly close in both flavor & body to shots prepared using my K10. Compared to the Lido 2 which I also own it is much easy to use & so far it seems to bring out more flavors in the shot then my Lido 2 does. At some point when I have more time I'll do some back to back testing.

orphanespresso wrote: Simply the desire to move the conversation away from the concept of choking a machine as a relevant test for espresso grinding adequacy. No more, no less.

That's actually a good point, and part of the reason why I gave the ROK a shot. I was able to modify my capresso infinity fine enough for acceptable espresso, but with too high 'fines' content (although that's an overly broad term in this context)- so anything really interesting going on in the beans was muted by overextracted ultrafine particles.

Sure wish someone would step in and run some more scientific tests on this thing. Hopefully someone does a grinder shootout with all the high-end hand grinders and a few of the more popular espresso-oriented electrics out there.

For my money I'm very happy with the grinder, so far. I've used (or tried to use) my hario mini for espresso and it was a miserable experience. sore hands and barely drinkable shots were all I got out out of it, the rok has been an absolute joy to use in comparison.

Good to hear.
I'm still unable to get a fine enough grind for my LaPavonni Pro.
I tried realignment, I will try it again soon. I get burr contact while grinding but still, not fine enough.