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Thread: How fine can your Rocky grind?

  1. #1
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    How fine can your Rocky grind?

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hello everyone,
    Just wondering if fellow Rocky owners could tell me how fine do their Rockys grind?
    Can your finest setting choke a Silvia?

    The reason I ask, is that I unpacked a new Silvia and Rocky a couple of days ago, and since then I havent had a drinkable cup of coffee using the Rocky to grind the beans. Every cup has been a gusha *>:(. I mean 5 sec gusha not a 15 sec one.

    On the finest setting on my Rocky, I cant choke the Silvia. I have adjusted the top burr so that zero on the dial really means zero (or close to it). If I go one click under zero, I hear the faint whirr of the burrs touching. But even at this setting I keep getting gushers. If others are choking their machines with the finest setting, then could there be something wrong with mine *:(

    I know that grind is only one part of the espresso process. I have been making espresso for about 6months (though on a cheap machine) and have been getting good results. I know about dosing and tamping and using fresh beans (roast my own) etc etc. Not that Im an expert by any means. Using the Rocky grind, I have tried dosing the double basket with 10g, 12g, 14g & 16g. I have tried tamping at 25kg and 30kg. I have tried dosing so no screw head shows on the top of the coffee, Ive done it so there is a faint impression and also a deep impression. All with the same result.... gusher *:(

    My old grinder was a Sunbeam EM0480 and when I grind the beans in this, I can get a reasonable espresso from the Silvia. So I presume that my dosing/tamping technique cant be all that bad. The grind I use from the EM0480 in the Silvia does feel finer than the finest grind on the Rocky. So could it be the Rocky?

    I know that when adjusting the top burr on the Rocky, when both burrs faintly touch, it sounds more like a bent bicycle wheel going round. Could it be that the burrs arent perfectly parallel with each other which could explain it producing a courser grind. Is this feasible? I have read Mals reply to another question about getting fines in the coffee. He mentions using PlastiGuage to test the gap between the burrs though I havent tried it yet.

    So really, if I know how fine others Rockys go, then I at least have a starting point as to whether mine is "normal" or not and whether it may need a trip back to the shop.

    Thanks.

  2. #2
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    Re: How fine can your Rocky grind?

    Hey Jacs

    Wow, sounds frustrating and to be honest i dont have a proper answer, though i did have a similar problem so might be able to help a snippit of your question

    I had that noise with my grinder as if the burrs were touching once per revolution when they were really close (about 3 clicks above the actual touching point). Ive been told that this is because the burrs arent perfectly parallel (as you said) and that it is not actually the cutting bits of the burrs touching but another part of the aparatus, so the sound is not actually the burrs grinding themselves away (phew). So now im often grinding on the setting a few clicks above the touching point and i find i have to to get a good extraction time. If i turn the empty grinder on at this setting i can hear this noise (and hear it slow down as the RPM slows after releasing the grind button). Strangely this disappears if you wiggle the hopper thing. And its not audible if there are actually beans in the grinder. You may have read the thread where that was discussed. The link to the video is http://www.youtube.com/watch?v=UMhbXh6s8X8

    In answer to your last question (well, im not sure how to answer it really but i hope this isnt totally useless!); my rocky seems to grind fine enough for my silvia but i generally only use settings "2" and "3" (above point "0" which I adjusted for). I did think this was odd and asked some people if there was something wrong with my rocky but I dont actually know.

    When i first heard this faint whirro f the burrs touching i thougt that this was the point "0" that everyone talked about but it seems that that was point "3" or so and if I clicked it down lower (with the machine unplugged and moving the burr by hand) I found the "0" point when the actual burrs touched.

    Maybe what you described as the faint whirr of the burrs touching at attribute to point zero is actually a few clicks above zero and is a result of that non-parallelness, so maybe you are grinding on say, setting "5" or something and can actually grind a bit finer??? Does that make sense?

    Hope that helps
    -S

  3. #3
    Senior Member GregWormald's Avatar
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    Re: How fine can your Rocky grind?

    My Rocky sits on #6, and with 18 gm of coffee in a VBM Domobar with double basket, I am getting great ristrettos in 20 to 25 seconds, depending on the beans.
    It also grinds much better since I did the teflon tape mod on the top burr holder threads. It was a very easy mod and tightened up the adjustment and eliminated any movement of the hopper/top burr. I now get a very even grind with no "fines" at all in the cup.
    You mentioned fines but didnt say whether you were getting any. If you have both fines and a gusher I would presume your burrs are not level--i.e. some coffee is overground, some under.
    Id be phoning my retailer and giving them the story, and seeing what they recommend. It certainly doesnt sound right, especially if your older Sunbeam is doing a better job.
    Greg

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    Re: How fine can your Rocky grind?

    What is the teflon tape mod on the top burr holder threads ??

  5. #5
    Senior Member greenman's Avatar
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    Re: How fine can your Rocky grind?

    Ive been grinding on 3/4 depending on roast and getting great shots (most of the time!!).
    Im interested to hear about "teflon tape" trick...............

  6. #6
    Mal Dimal's Avatar
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    Re: How fine can your Rocky grind?

    Quote Originally Posted by argon link=1205108522/0#3 date=1205128413
    What is the teflon tape mod on the top burr holder threads ??
    Actually,

    If you do a search of OzScotts recent threads (say 3-4 months ago), he has come up with a better mod for achieving the same level of control and also looks pretty good to boot,

    Mal.

  7. #7
    Senior Member GregWormald's Avatar
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    Re: How fine can your Rocky grind?

    Rather than have you all searching your little hearts out--here is the "Teflon tape mod". Thanks to the inventors.
    The idea is to stop any slop in the threads that raise and lower the top burr. Check for slop by trying to wobble the hopper when it is set for your favourite grind. If it moves at all (other than rotating for adjustment) do the following:
    1. Take off the hopper by unscrewing the 3 screws you can see by looking into the hopper.
    2. Unwind the brass burr holder by unscrewing counter-clockwise.
    3. Wind enough plumbers teflon tape around the top of the threads. (Mine took 3 layers to tighten right up.)
    4. Put Rocky back together. Screw brass burr holder back on until it just touches the bottom burr. Back off a quarter of a rotation or so until the hopper fits back on and gives you the same zero you had before. (You can only be 1/3 of a rotation out so its not a disaster if you miss the correct # the first time. Fiddle until its right.)
    5. Enjoy a no-slop adjustment that holds the top burr steady.
    On my Rocky this reduced the fines in the cup to zero--so Im guessing the burr doesnt change adjustment because of the slop in the threads.
    (BTW--I had to do it twice to get it right--the first time was too hard to screw because of too much tape.)
    Greg

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    Re: How fine can your Rocky grind?

    The reason I ask, is that I unpacked a new Silvia and Rocky a couple of days ago, and since then I havent had a drinkable cup of coffee using the Rocky to grind the beans. Every cup has been a gusha Angry. I mean 5 sec gusha not a 15 sec one.

    On the finest setting on my Rocky, I cant choke the Silvia. I have adjusted the top burr so that zero on the dial really means zero (or close to it). If I go one click under zero, I hear the faint whirr of the burrs touching. But even at this setting I keep getting gushers. If others are choking their machines with the finest setting, then could there be something wrong with mine cry

    I am pleased with my teflon taped Rocky but in your case return Rocky and Sylvia to the retailer and get them to sort it for you, I taped mine after retailer returned it to the distributor, the distributor sent it back as is, with the response it grinds doesnt it :-?, so I taped and continue to tape it after the odd clean, it grinds nice and consistent to my satisfaction.
    >:(Take it all back and get them to sort it. >:(

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    Re: How fine can your Rocky grind?

    Hi jacs,

    My Rocky is 3/4 months old and has performed flawlessly from new.
    My highest grind setting for Silvia to produce wonderful espresso has been 10 and my lowest has been 7, depending on coffee beans and who roasted them. ie. me or commercial roaster. With my freshly roasted beans I have stopped Silvia down around the 7 mark. 0 really is zero on my Rocky and I use about a 16kg tamp. My usual grind would be around 8.
    It sounds as if you have a problem with your Rocky and as others have said, go back to your supplier and get them to fix it.
    All the best with it.

  10. #10
    Mal Dimal's Avatar
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    Re: How fine can your Rocky grind?

    Heres the link to OzScotts Rocky Mod.... http://coffeesnobs.com.au/YaBB.pl?num=1200380249/0
    Took me all of 20 seconds to locate :-?

    Mal.

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    Re: How fine can your Rocky grind?

    Thanks everyone for your replies.

    I used PlastiGauge to see if my burrs were parallel and found that they are not. Not that they are out by any great amount, but the strips of PlastiGauge were certainly of different widths, one in particular. Are all Rocky burrs perfectly parallel? Is the difference enough to alter the grind to any great extent? Questions, questions......

    Sanch, the video could actually have been taken of my machine. I think the reason the noise stops when you wiggle the hopper, is because of the play in the top burr and also because the locking pin doesnt fit tightly. As you move the hopper, so does the top burr. The tape trick helps with all those things. Ive also put a wedge in the side space next to the locking lever. This really stops any possible rotational movement.

    I had another thought last night. Could the Silvia be pumping out too much pressure? Ive certainly read enough about some coming out of the factory with rather high pump pressures. If it is too high, then it certainly wouldnt be helping my cause too much. Im currently trying to rig up a decent blind filter so I can do the cc/min flow test. I am guessing that this is prone to inaccuracies, but it should give me some idea if the pressure is too high or not.

    The quest continues....

  12. #12
    Mal Dimal's Avatar
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    Re: How fine can your Rocky grind?

    Quote Originally Posted by jacs link=1205108522/0#10 date=1205193135
    Thanks everyone for your replies.

    I used PlastiGauge to see if my burrs were parallel and found that they are not. Not that they are out by any great amount, but the strips of PlastiGauge were certainly of different widths, one in particular. Are all Rocky burrs perfectly parallel? Is the difference enough to alter the grind to any great extent? Questions, questions......
    Gday jacs......

    Yes, ideally the burr-plates should be perfectly parallel if all threads have been cut accurately. My Rocky (since sold to another happy CSer) after plastigauging was quite satisfactory, within 0.0005" at the four points of the compass. So yes, I would say that most Rocky grinders have satisfactorily parallel burr-plate faces. Not sure what tolerance limits are acceptable to Rancilio though.

    My current grinder a La San Marco SM-90A, has perfectly parallel burr-plates for example.

    I had another thought last night. Could the Silvia be pumping out too much pressure? Ive certainly read enough about some coming out of the factory with rather high pump pressures. If it is too high, then it certainly wouldnt be helping my cause too much. Im currently trying to rig up a decent blind filter so I can do the cc/min flow test. I am guessing that this is prone to inaccuracies, but it should give me some idea if the pressure is too high or not.
    It is possible mate.... Especially if your Silvia is an older model before the adjustable OPV was fitted and calibrated at the factory. If this is the case, you will need to search for the Silvia Pressure Mod which details the steps to follow regarding the fitting of small washers under the cap of a fixed OPV valve to reduce the set pressure.

    All the best :),
    Mal.

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    Re: How fine can your Rocky grind?

    Hi Mal,
    I think it is about time I checked my Rocky too for burr alignment but cant find anywhere that sells Plastigage [except in the USA].
    I tried a Google search and Repco and Autobarn online search to no avail.
    We live rural Sth Western NSW.
    Any ideas would be greatly appreciated.
    Thanks.
    Herbie

  14. #14
    Mal Dimal's Avatar
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    Re: How fine can your Rocky grind?

    Gday herbie,

    Our local Repco sells the stuff so maybe you just need to drop in and ask em. Most automotive engine repair shops would have it too Id reckon and might be willing to give you a small amount or sell you some....

    Cheers,
    Mal.

  15. #15
    Senior Member GregWormald's Avatar
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    Re: How fine can your Rocky grind?

    Hi all,
    As I was playing with OzScotts Rocky mod I found another way that both turns it into a stepless grinder, and stabilises the upper burr holder.
    Take off the hopper, unscrew the top burr holder and then wind a piece of 6mm or 4mm plastic tubing around the holder, at the top of the threads. Secure by threading a thin wire or nylon string through the tubing and tying it tightly.
    Screw the burr holder back down and the tubing gets squashed (about # 12) and acts as a spring.
    I dont know yet if the tubing will take a set and the mod will fail, but at the moment it works a treat--tightening the adjustment so it doesnt move even when the lock is disabled, and forcing the burr carrier up so any slop in the threads is negated.
    Ill let you know if I run into problems, no notice means it continues to work well.
    Greg

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    Re: How fine can your Rocky grind?

    Just an update on things.

    Firstly, herbie I bought my PlastiGauge from Repco. It comes in different colours in relation to what sort of tolerance you want to measure. I bought the yellow which seemed to work fine. Cost me a little over $8 for one strand. Its only about a foot long, so dont waste it, though you only need to use 4 pieces that are 5mm or so.

    After testing the Silvia with the cc/min test, I discovered as best I could, that the setting is already pretty spot on, so thats not the problem. So I contacted the dealer and they said for me to send the Rocky back and they will test it and if there is a fault, they will send me another one. I sure hope its the same for them as for me. Ive been trying to wrack my brain to make sure I have covered everything. Though when I follow the exact tamping technique etc but simply grind the beans on the sunbeam, then the Silvia pours a good shot. So surely it HAS to be the Rocky, because I simply cant grind any finer on the Rocky otherwise the next notch down has the burrs grinding together. So heres hoping.

    Nice mod Greg. Just wish I had a Rocky I could try it on :(
    Itll be interesting to see how it lasts.

  17. #17
    Senior Member GregWormald's Avatar
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    Re: How fine can your Rocky grind?

    When the plasti-guage gives the same reading from all around the circumference, and Rocky still works worse than your old Sunbeam, there has to be something else wrong.

    As far as the latest mod goes--I really like it. Being able to tune the grind without separate steps, and pushing the threads tight has enabled me to improve my shots again. The last three coffees have had a greater depth of flavour as I can now get exactly the the length of draw I want.

    If the plastic tubing doesnt last then I do have some surgical rubber tubing that I know will not take a set.

    Good luck with your Rocky and I hope its working well when it comes back to you.

    Greg

  18. #18
    Senior Member greenman's Avatar
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    Re: How fine can your Rocky grind?

    I have just done the teflon tape mod on my Rocky and it has firmed up the burr carrier and there is no apparent play there now.
    Next step will be the stepless mod with the tubing!

  19. #19
    Senior Member ozscott's Avatar
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    Re: How fine can your Rocky grind?

    The plastic tubing has served me well and is not wearing - perhaps the small adjustments minimise wear and there is no play - the shot improvement is quite significant from this mod...

    Cheers

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    Re: How fine can your Rocky grind?

    Ozscott, that plastic tubing mod really is great.
    I agree that being able to make the smallest of alterations really does make a big difference to the shot.
    Nice to know that its wearing well.

    With the tubing I used however, it allowed the hopper to still rotate around a bit too freely. I simply put another layer of tubing over the other one, and now its rock solid. Maybe even a little too solid, but since I only grind for espresso and the alterations are only a few mms at a time, this suits me fine.

    Even though the Rocky is pretty quiet to start with, this mod seems to make it even quieter!

    Great stuff.

  21. #21
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    Re: How fine can your Rocky grind?

    Did Jacs get the Rocky problem solved in the end?

    I may cough up for a Rocky soon and for $400 you should expect them to grind fine enough. Like cars you can always get a lemon I guess

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    Re: How fine can your Rocky grind?

    Gday Beanhead,
    I actually ended up returning my Rocky to the vendor, and they agreed that it was not grinding as it should. They were really great about it all and their service was some of the best I have ever experienced. I asked them to test the replacement one before they sent it to me, and they did just that: grinding and then making an espresso with it. I have since been using that grinder for a number of months and it is performing very well. I now grind for most beans at around 3-4 notches above true zero. However, I bought some Mountian Top Estate at the last beanbay auction and I have to grind those at around 7-8. So as you say, there is always a chance that you may get a lemon. Also, if you get a Rocky, there are two mods that I found to be essential: Put some thread tape around the top burr carrier to take up the little bit of wobble that seems to be in all Rockys and the plastic tube mod that is mentioned in this thread. Both are really worth while and best of all, non-destructive.

  23. #23
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    Re: How fine can your Rocky grind?

    Hey Jac

    Thats good news as I finally bought a Rocky whilst waiting for my partner to come out of the dentist (relegating my hand grinder to holidays). *I got it at DiBartolis with a CS discount. *Rockiies have been getting a some bad rap of late so it might be worth pointing out why I went the rocky over the IC, Ascaso Mini etc

    1. *More kilos of grinder for your dollar. *The extra weight is either due to the armour plate cladding (albiet cut in a rush by some underpaid over worked Italian) or a much beefier motor.

    2. The grinder has been around for yonks so it will be centuries before spare parts will not be available any more. *Name me another appliance that doesnt get remodeled every 6 months. *

    3. *Compact, doesnt take up much more bench space than the Ascaso Mini surprisingly. *

    4. *Stepped adjustment which means the grinder will pay for itself if it means that better plunger coffee at work means I dont spend so much on espresso down stairs. *

    5. *The rockies dont seem to devalue so much. *People seem happy to buy a second hand rocky but not so happy in a second hand EM0480. *This is an issue if my doctor tells me to give up coffee as a matter of urgency. *

    6. *Has some sort of old world charm about it like a Harley or something.

    7 A contribution to the ailing Italian economy. *

    Once out of the dentist and in at Bartolis my partner was a bit disgusted that I should want to spend so much on a grinder (she doesnt drink coffee). *I tried to reassure her that this is the Rolls Royce of the domestic grinder world, that she spent $4000 on a sewing machine and never regretted it, and just spent $4000 on her teeth a minute ago. *She was placated more or less, partly due to me being almost as excited on purchase as when our son was born. *

    It is now in its box next to my desk, look forward to getting home, hope it works. *Will look into the mods as i like to tinker..


    Jason

  24. #24
    Mal Dimal's Avatar
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    Re: How fine can your Rocky grind?

    Quote Originally Posted by Beanhead link=1205108522/20#22 date=12137585471. More kilos of grinder for your dollar. The extra weight is either due to the armour plate cladding (albiet cut in a rush by some underpaid over worked Italian) [b
    or a much beefier motor[/b].
    Definitely down to the motor Bh.... The Rocky uses the same internals as the Rancilio MD4 Commercial Grinder but mounted in a more compact case. I dont think youll ever break it and so long as its working perfectly straight out of the box, it will last you a lifetime 8-).

    Happy Brewing :),
    Mal.

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    Re: How fine can your Rocky grind?

    Quote Originally Posted by Beanhead link=1205108522/20#22 date=1213758547
    She was placated more or less, partly due to me being almost as excited on purchase as when our son was born.
    Loved this line. :D :D

    Good luck with the new grinder, mate. :)


    Cheers..................Sean

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    Re: How fine can your Rocky grind?

    Some mighty fine points there Jason that I can definetly relate to.

    Let us know how the new baby is working out.

    Al

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    Re: How fine can your Rocky grind?

    ...and Griffin weighed almost weighed as much as Rocky when he was born...

  28. #28
    Senior Member ozscott's Avatar
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    Re: How fine can your Rocky grind?

    jacs - good point - I noticed that it got noticeably quieter also...best of both worlds. Glad to hear yours is doing well. Great grinders these, particularly with an easy mod.

    Cheers

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    Re: How fine can your Rocky grind?

    Sorry to bring this post back.....but:

    For those who have done the plastic tubing mod, does it make the rocky stepless?? Do you have to disable the little pin to stop it locking into the hopper (ie. stepped), or does the tubing raise the whole thing enough that the locking pin cant reach the hopper? (I wouldnt think so as the burrs still have to be same distance appart to pull a shot!) Hmmm???

    Also, im assuming with the plastic tubing mod there is no reason to do the teflon tape mod, as the tubing acts as a spring, taking up the slack in the holder threads??

    Thanks
    :)




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