I bought this coffee grinder (Hario Mini Mill Slim model MSS-1B) because I was tired of my whirly blade and the ability to get decent larger grind sizes without excessive dust. I also didn't want to spend more than $40, and wanted to replace my Cuisinart because produced significant amounts of dust along with just-barely-acceptably consistent grinds (not to mention it was loud as heck).
Out of the box, the grinder comes with no basic English instructions. Operation is intuitive, though:
Grind settings are set by a screw on the drive shaft. Attach the handle to prevent the main shaft from turning, screw the adjuster all the way down, then back off X number of "clicks" each of which is approximately 1/6 of a turn of the screw, or approximately 0.15-0.20mm each "click". One or two clicks will be in the range of espresso, 12ish clicks will be Press Pot. Drip will be somewhere around 8-11 clicks.
Grinding consists of loading the hopper with X grams of beans, screwing on the receiver (which locks the outer burr in place), installing the clear cover (which also stabilizes the main shaft sleeve) applying the crank and turning it until the grinding noise stops and you feel no resistance.
Cleaning is also easy, the central adjuster nut unscrews, the central burr can be removed and cleaned. The outer burr is keyed to the hopper/housing, and also removes easily for cleaning. It has four locator key points to note when installing.
Further disassembly is not necessary for normal maintenance, but is also fairly easy - the central burr spring slides off the keyed drive shaft, and the whole shaft can be pushed up out of the sleeve. There are two bushings at either end, be careful not to lose these. The central rotating burr has a plastic keyed insert that can also be removed for more detailed cleaning.
The ceramic inner and outer burrs appear to be high quality.
Inspection of the grinder during operation, especially with large grinds (12 clicks) shows significant slop, wobble, or play of the central burr. This is the main reason for inconsistent grind sizing and generation of dust. While grinding, one side of the burr is almost no clearance, while the other side has doubled in size. If you are looking for 1.5mm pieces consistently, you can end up with 2mm pieces mixed in with 30% "dust".
The key is eliminating as much of this slop as possible, and ensuring the outer and inner burrs are concentric. On this grinder, these inconsistencies come from the following areas (in order of importance);
-Excessive clearance of the main drive shaft to the sleeve (upper and lower bushings and sleeve, creates a sideload-dependent eccentricity of central burr during grinding [about .75mm play])
-Excessive clearance of the outer burr to the housing/hopper (when locked in place during grinding with the receiver, it can be locked in place off-center to the central burr [about 0.4mm play])
-Central burr is not tight to its plastic keyed attachment (wobble during operation when beans are being ground [about 0.2mm play])
-Central burr keyed attachment is not tight to the central drive shaft (wobble during operation when beans are being ground [about 0.2mm play or less])
With some scotch tape, high-molecular-weight tape, or even packing tape, these clearances can be effectively eliminated by disassembling the unit, applying tape to the bushing areas on the drive shaft, applying tape to take up the clearance of the outer burr so it is consistently centered on the housing/hopper, and applying plastic in key areas to tighten up the central burr motion on its plastic keyed attachment. Discovery and discussion of these modifications are here: http://coffeegeek.com/forums/coffee/questions/530253#530253
In all, I really like this little device, I liked it out of the box (even with the slop, it produced consistently better grinds than a whirly blade or my Cuisinart), and I love it now that it is functioning properly. It is compact and quiet, and produces very good grind for my needs. It is positioned at a very good price point, and in my opinion is a good to excellent value depending on whether you want to spend 90 minutes to make some minor improvements.
I hope that in the future, Hario figures out a better way of getting a consistent location of the inner and outer burrs on these mills. I have heard that the Skerton also suffers from some of the same issues, and also has people modifying that grinder to work better. If they ever figure it out and keep the price point under $40, I'll be one of the first in line to get one, because it will become an excellent, consistent, hi-value grinder.