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Burr alignment - wow!

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  • Burr alignment - wow!

    I've had issues getting consistent shots and had been setting my Quamar Q50 finer and finer. I'd even changed bean supplier because I thought my regular roaster had changed something. The settings were almost at zero - as in burrs touching.

    As well as variation in shot timing, I also noticed it was about 10 to 12 seconds after the initial drops for streams to join into a single stream. I changed to another roaster and had some better results, but still not consistent.

    I then read a couple of posts about aligning the burrs - making the burr carriers coplaner and the use of shims. I looked into the burr carrier fixes as per Scott Rao's blogpost on the EK43. I suspect my burr carriers are not parallel - in fact I'm certain because there is a bit of play in the thread for the top carrier. I wanted to try the EK43 fix on mine, but the rim on which my burrs sit is only about 3mm or less, so trying to get sandpaper to stick to that is difficult. (The bottom of the EK43 burrs are wide and flat.)

    So I spent an hour or so with a whiteboard marker and shims and now my burrs are parallel (almost - more later) and wow the difference is remarkable.?
    1. My grinder is now around 3-4 steps off zero.
    2. My shots now go straight from the initial drops to a single stream (used to have 2 or 3 initial streams)
    3. Every shot at the one grind setting runs within +/- 1 second.
    4. The crema is thicker and has more of the "chocolate" look about it.
    5. The taste is much more consistent.
    I guess with the burrs out of alignment, the variation in my grounds was such that it was just luck on the fine/coarse ratio.... and to get an average, I had to grind some way too fine.

    The issue I still have is with the design of the burrs, where the seating rim does not support the bolt holes, so tightening causes the burr to dip at that point and causes what I have learned is called "Taco Burr Syndrome".
    https://www.home-barista.com/forums/...27-wa0000.webp
    https://www.home-barista.com/grinder...t59857-10.html

    I need supports under the bolts to get a perfect result, but finding six identical spacers that are all 1.5mm (or thereabouts) is my next challenge. Either that or I'll use the low strength Loctite with less torque.

  • #2
    Good work. With that much correction on the dial I'm not surprised that it's working better.

    finding six identical spacers that are all 1.5mm (or thereabouts) is my next challenge.
    Hobby shops are an excellent place to find brass strips in various thicknesses for shimming

    This one is 0.032" which is about 0.8mm (or multiples of)

    https://www.hobbyone.com.au/k-s-bras...-x-2in-1-strip

    Or you can find it in half the thickness (0.4mm) if you want to stack in half mm amounts.
    https://www.metrohobbies.com.au/prod...-4-brass-strip

    Comment


    • steve7
      steve7 commented
      Editing a comment
      And should adjustments be needed, brass would have the advantage of being able to be sanded down a little more easily than the stainless steel washers I was thinking of.

      Thanks for the tip.

    • amberale
      amberale commented
      Editing a comment
      A cheap set of feeler gauges can be cut up for shims.
      Gives a lot of options from one set.

    • steve7
      steve7 commented
      Editing a comment
      Thanks to amberale for the feeler gauge tip. One of the burr carriers had a 1.6mm gap underneath the bolt hole and the other had 0.3mm. The feeler gauge leaf did the trick nicely. I lucked into having a 1.6mm brass bar that suited the other. The burrs now look to be perfectly aligned - whiteboard marker rubbed off all round on both.

  • #3
    You have me thinking....I know the burrs are not perfectly aligned, but given the cost of the grinder I wouldn’t expect high precision.

    Time to dust off the dial gauge and check how flat the burrs are then do some tinkering.

    Comment


    • #4
      I spent the afternoon fiddling with the grinder.

      I shimmed the bottom burrs with some very thin hard plastic that I could layer until it was the correct thickness. This has resulted in a runout of about 0.013mm (0.0005” on my ancient dial gauge).

      The top burrs are a different story altogether. The casting for the carrier has been poorly machined resulting the top burrs being out of parallel with the bottom burrs by about 0.25mm.

      With a lot of fiddling I have them close, but there is still more to go. I might look at machining it for a better fit.

      Its too late in the day for a coffee, so the test will have to wait.

      Comment


      • steve7
        steve7 commented
        Editing a comment
        0.25mm is massive in coffee language. Good luck. Once done you will then spend the next 30+ minutes dialling in new settings.... although with the consistency after I did mine, dialling in was very fast.

        Have a search for EK43 burr alignment - it's a pro grinder but there are a couple of results on shimming the burr and on making sure the burr carriers are parallel (I think coplanarity is the term) - and the techniques are relevant to most grinders. The link I put in above relates to a Baratza, but again relevant to most.

        I have a dial gauge but the whiteboard marker was probably as good or better. Cleaning it off was a pain and despite running a few doses through for cleaning, I think I still had the taste for a few coffees.

    • #5
      I can report that my grind setting has changed immensely after taking into account the difference in the scale.

      Normally I would have the burrs so close they were chirping before the beans were added. Given the play in the thread the burrs shouldn’t have been touching (or perhaps just a little) when grinding. My original recipe was 22.7g (less with fresher beans) in with about 35-40g out for my morning latte.

      After the tinkering my first shot was set up with the burrs one step back from chirping and 20g and the machine was completely choked.

      I have now had to back off two steps with 22.5g to get it where I want it. I may need a smaller basket..

      I ended up using foil to shim the top burr and then measured the total thickness to estimate the misalignment. It was quite time consuming creating the stepped layers to properly support it.

      On closer inspection it would be too difficult to machine the tolerance to an acceptable level, but using emery paper should work.

      Thank you steve7 for providing the impetus to improve the grinder.



      Comment


      • steve7
        steve7 commented
        Editing a comment
        ? Glad to hear.

        But importantly - is there a taste difference? (and good or bad?)

      • Dipendente
        Dipendente commented
        Editing a comment
        Yes, there is a taste difference. I had and espresso and latte - both were better, especially the espresso.

        My beans are stale and will get some fresh ones on Wednesday, so that will be the real test.

    • #6
      Hi everybody! I'm having the same problem with my recently acquired quamar q50e. I cleaned up the threads and am sure things aren't cross threaded. No matter now close I get the grind is not fine or consistent. Can someone please walk me through the process of shimming the burrs and or shaving down the carriers. Also I am having trouble getting the bottom burr out of the carrier. Some advice on removing the bottom burr/carrier would be greatly appreciated.

      On a side note I will say the grinder looks beautiful but I'm disappointed with the build quality of the grinder. It seems all the components are made of aluminum when often a stronger metal would have been more appropriate.

      Comment


      • #7
        Have a look at this

        https://youtu.be/5-cf0Iack5Q

        I wouldn't do any destructive changes unless you are really confident that you have diagnosed the problem correctly.

        Cheers

        Comment


        • steve7
          steve7 commented
          Editing a comment
          That's the video that got me thinking about this issue - then I saw Scott's blog on other issues.

      • #8
        A big thank you!!! After 2 hours of tinkering it works great! I currently have a Compak k7 Silenzio with a dosser standing next to the Qamar Q5E They are husband and wife lol.

        Comment


        • steve7
          steve7 commented
          Editing a comment
          But does the coffee taste better?
          And do you get more consistent shots?

        • BeyondMyMeans
          BeyondMyMeans commented
          Editing a comment
          Yes and yes. Before the shimming I was unable to get the fine, soft, consistent grinds necessary for a decent shot on my Pasquini. I'm loving the form factor and anti static chute. So grateful for you sharing this.
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