Results 1 to 7 of 7

Thread: The quality of my Rockys grind is worrying me

  1. #1
    Member
    Join Date
    Dec 2007
    Posts
    53

    The quality of my Rockys grind is worrying me

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi all,

    I have a rocky grinder and quite frankly im a bit worried about the quality of the grind im getting out of it.

    To get a decent coffee out of my silvia I have to set the rocky to around 3 or 4. When set to 4, I fill the (stock) double filter basket, give the portafilter a few good bangs against the counter top to settle the grinds, grind again to fill it up, level with the back of a knife and tamp. This produces a pretty pleasing flow.

    I have a few concerns about this, however:
    - Firstly, it seems to me that 3 of 4 is way too low of a setting to be reasonable. From memory, if there are no beans in the grinder then it will go down to "0" as the lowest setting. Thus, Im grinding at 3 or 4 above the "0 point" . Honestly Id prefer to be grinding at 3 rather than 4, but 3 is scarily close to the 0 point. From recollection, most people grind at around 6 above the 0 point
    - If I run the grinder when set to 3 or 4 with no beans inside, the grinder makes a somewhat ugly metalic sound. presumably this is because the burrs are touching at this low setting. From memory the metalic sound stops when set to around 6 or higher
    - Although this makes a fairly tasty coffee with plenty of crema, Im always left with coffee grinds in the bottom of my cup. This suggests to me that maybe it is an uneven grind and some grinds are so small that theyre getting through?

    Whats everyones opinion on this? Is this normal and Im just paranoid, or is something wrong with my rocky? I suspect that Im getting an uneven grind which is forcing me to grind at an unusually low setting in order to get a decent "average" size of grindings. I fear that this may be caused by the known issue of some rockys having the burrs somewhat off-centre

    Unfortunately I bought the rocky interstate so sending it back is a pain. Ive already sent it back once because it was providing a poor grind, and I just want to confirm with coffeesnobs before I send it back again.

    And for the record, Im using fresh beans etc etc

    edit: Rocky is doserless, silvia is stock (not done pressure mod or anything) and is the newer model (with the different design on the drip tray thingo - i think the new models are at a different pressure or something?). beans are Merlo and roasted days prior

  2. #2
    cremakid
    Guest

    Re: The quality of my Rockys grind is worrying me

    look at this http://coffeesnobs.com.au/YaBB.pl?num=1202554263 maybe you are not alone, maybe just a matter of when not if.

  3. #3
    Member
    Join Date
    Dec 2007
    Posts
    53

    Re: The quality of my Rockys grind is worrying me

    Yeah Ive read that topic. I put it aside when I saw "lavazza" though ;)

    It sounds like we may have a similar problem; which is related to a problem that I have read about on the internet before.

    However, being that I read about the problem prior to receiving my rocky, I could just be paranoid! The filings in the bottom of the cup really concern me though.

    The first time that I had the rocky, i could never get it to grind fine enough because it made a metalic sound at setting "6" and I did not dare to go any lower than this. Set anywhere above 6 and the grind was far too course. I sent it back to the supplier who tested it, agreed that it was too course, got it "repaired" and sent it back to me.

    Since it was damaged in the post on the way back to me, I decided to take the risk and go below the "metalic sound" point on the grinder (since id be sending it back anyway). Below this point I can finally get a fine enough grind to get enjoyable coffee, but im worried about the coffee filings and the fact that its set so low

    It may be possible that my true zero point is below "0", and that the burrs simply stop at "0" due to the protection screw. Someone in the thread that you linked to said that they removed the protection screw and found that their true zero point was actually at -5. If my true zero point was actually at -5, this would explain why I have to set the grinder to 3 to get good coffee. However, this would NOT explain the coffee filings, nor the metalic sound that starts at "6" and below.

    I dont particuarly want to remove the protection screw for fear of voiding my warranty. However. I do want to come to the bottom of my problem prior to sending it back, to ensure that they actually fix it this time. The first time that I called the australian rancilio rep i was told, snobbishly, by the rep that there was nothing wrong with my grinder (this was while it was still at my home and they hadnt even looked at it), and that you cannot beleive what people say on the internet. I want to be sure that something is wrong before dealing with him again.

  4. #4
    Mal Dimal's Avatar
    Join Date
    Oct 2004
    Location
    Warwick, QLD
    Posts
    16,878

    Re: The quality of my Rockys grind is worrying me

    Gday hugz,

    Sorry to hear that you are having concerns with your Rocky. I spose there are a couple of relatively quick checks which will either identify the existence of a manufacturing problem, or discard the notion altogether.

    With Rocky unplugged from the power outlet, follow this guide re: the disassembly and cleaning of Rockys internals. Once you have the Top Burr Carrier/Hopper assembly removed, just set these aside for the moment.

    You will notice that theres a very high Dome Nut securing the Lower Burr-plate to the Motor Shaft. Making sure that the Nut is clean and has no coffee-oil residue on its surfaces, try to pull the shaft up as hard as you can, just using your fingers (or with the aid of one of those small rubber matt things for opening tight jar lids), then push it down, and see if you can observe any axial play in either direction.... there should be none. Do the same thing laterally this time in a Compass Rose fashion (NSEW) and likewise, there should be NO play in this plane either.

    The next exercise requires the acquisition of some "PlastiGauge" which can usually be obtained quite cheaply from any mechanical spares suppliers like Repco, for example. If you are not sure about how to use this, Im sure that one of the Repco PBTC will be able to explain the process to you, it is very easy to use. You need this stuff in order to easily measure the clearance between the two burr-plates once the Top Burr Carrier is temporarily re-attached to the lower section. You will also need to either temporarily or permanently remove the Zero Stop Screw so that you can establish where True Zero lies for this measurement. You should mark this in some way for future reference as a "datum point". Wind the top burr back out say 6 steps on the scale and mark this as another datum point.

    With the top burr-carrier removed again, attach small lengths (3-4mm) of PlastiGauge "radially" on the very periphery of the bottom Burr-plate at 90 degree intervals, where the 3-4mm flat section has been ground to prevent the burrs from trying to "grab" when they make contact. The PlastiGauge needs to be placed radially since the most reliable means of measurement of the clearance will have to be made "circumferentially". Wind the Top Burr Carrier back down until you reach the datum point thats about 6 steps back from True Zero. This will probably require more than the usual force to be applied as you squash the PlastiGauge material between the two burr-plate surfaces. If it proves too difficult to wind the Top Burr down to the #6 datum point, just take it as far as you can and then wind it all the way back out again. If it looks as though the motor shaft has been turning once the PlastiGauge makes contact with the upper burr-plate, you may have to put something "up the spout" of Rockys discharge chute to prevent this from happening.

    Ok, now you can measure the width of each piece of PlastiGauge and note any variance between them. If both the Housing and the brass Top Burr Carrier Threads have been cut "true", then all the pieces of PlastiGauge should be identical in width. If one or the other threads have not been machined accurately, then you will notice a variation in the width of each PlastiGauge section. The relationship of the measurements of each PlastiGauge piece and their relationship to the #6 datum point will provide you with an indication of just how square the Top Burr Carrier is to the Grinder Housing, and therefore the burr-plates as well.

    You could use other ductile materials instead of PlastiGauge for this purpose but it is designed to behave in a particular, repeatable way and is quite easily "squashed" compared to lead or antimony wire which is (was) also used for this sort of purpose. Its a bit of mucking around but at least it will provide you with factual irrefutable data that you can use to support a warranty claim if this should become necessary.

    All the best mate, and good luck :),

    Mal.

  5. #5
    Member
    Join Date
    Dec 2007
    Posts
    53

    Re: The quality of my Rockys grind is worrying me

    wow thanks for that big and informative post!

    interestingly, however, today i ran out of beans, and discovered that its making a horrible metalic sound no matter where its set to. something aint right, and its going back

  6. #6
    Mal Dimal's Avatar
    Join Date
    Oct 2004
    Location
    Warwick, QLD
    Posts
    16,878

    Re: The quality of my Rockys grind is worrying me

    No worries mate,

    Hopefully they will sort it out properly for you this time. Perhaps the info above will assist someone else who may be experiencing similar problems. Over the years I have always found that if you are able to provide factual supporting evidence to clinch the claim for a warranty repair/replacement, the whole exercise seems to go a lot more smoothly and quickly. Hope yours is sorted out quickly..... :)

    Cheers hugz,
    Mal.

  7. #7
    Senior Member greenman's Avatar
    Join Date
    May 2007
    Location
    Perth, Western Australia
    Posts
    3,156

    Re: The quality of my Rockys grind is worrying me

    Good one Mal, Ive been looking for a Rocky cleaning guide for a while and now I have one thanks!!



Similar Threads

  1. VBM - quality not quite there
    By garbage in forum Brewing Equipment - Pointy End ($1500-$3000)
    Replies: 45
    Last Post: 13th November 2008, 11:26 AM
  2. Fine grind/course grind blend...How To?
    By reubster in forum Blending Room
    Replies: 8
    Last Post: 5th December 2007, 02:37 AM
  3. Play in Rockys burr carrier thread
    By vicroamer in forum Grinders
    Replies: 12
    Last Post: 26th July 2007, 01:47 AM
  4. Rockys cracked nose
    By KoNG in forum Grinders
    Replies: 10
    Last Post: 5th January 2006, 03:55 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •