Ive been using a Tranquilo for a couple of months now. Im quite happy with it for the price. I particularly like the big hopper. Ive been getting some variation in my shots and thought Id take a look inside to see if it might be the grinder. I dont think it is. The upper burr is fixed to a machined metal burr holder which screws smoothly into a cast metal casing via a fine thread. So the adjusting mechanism seems quite solid. The casing is screwed to a base plate which holds the bottom burr and motor. The base plate is made of plastic albeit what appears to be a very tough fibre reinforced plastic. I would have been a little more assured if the base plate was cast metal also. Nevertheless it all seemed quite rigid.
I took the opportunity to measure the diameter of the burr. It was 60mm as per the user manual. However this surprised me since I thought I had seen references to it being 65mm. This is where things get confusing. The Cunill site shows an “El Café Tranquilo” cosmetically identical to mine but specified as having 65mm burrs. Elsewhere the site shows a “Café Tranquilo 2” (no El) with a burr size of 60mm and while not cosmetically identical, it is similar to mine. However, my machine is quite clearly labelled “El Café Tranquilo”. So beware, you may not be getting the burr size you think you are getting. Does it matter? Probably not. The Mazzer Mini has a burr size of 58mm. I don’t hear anyone complaining. In any case, provided the 3 fixing screw holes line up, there seems to be ample room to fit the larger burr.
Another issue was the void around the burrs. I don’t know if this is normal but I cleaned out about 2 shots worth of grinds that weren’t going anywhere. I can see that it is wise to have a fair clearance to avoid jambs but the thought of all that stale coffee is a worry.