A) Burrs / Grinding Plates for the La Cimbali grinder shouldnt be hard to get at all if you direct your enquiries to the importer of the brand in the country of your location. In Australia their HQ is in Melbourne but they have offices in a number of the capital cities.
b) If all is as you say and done correctly then the simple answer is most likely that the grinding plates are no where near touching, and usually what stops the adjuster with top plate from winding down any closer to its expected position is a build up of grinds turned into a rubbery paste in the female thread (the one in the body of the grinder). Remove the adjuster assembly, use a dry tooth brush or similar to clear the thread down to the bottom plate, clear the male thread as well, suck out with a vacuum cleaner and reassemble carefully so as not to cross thread and all should be well. ;)
c) Remember, commercial planar grinding plates should be good for atleast 400 kg (and longer depending on the type) so do a budget calculation on the use of any grinder before doing this type of job....it may not be necessary especially for a commercial type grinder used in a domestic (low volume) situation.
Hope that helps,
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