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Iberital challenge not grinding fine enough - burr alignment?

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  • kevinelp
    replied
    Re: Iberital challenge not grinding fine enough - burr alignment?

    Yay, think Ive solved my problem.

    I was still playing a balancing act between getting the grind fine enough, and avoiding metallic squealing noises - not good, so I could not resist more tinkering.

    Well this morning I managed grind fine enough to clog silvia, and avoid the squealing as well, heres how:

    I loosened the screws and bolts that mount the motor and gearbox to the based plate, thus introducing a small amount of movement to gearbox shaft and lower burr. I then screwed the upper burr all the way down until it engaged/locked on the lower burr - the two burrs should now be centered on each other. I then did the motor and gearbox screws up while carefully backing off the top burr at the same time, until the burrs were free and the screws done up tight.

    Bingo, less noise for a much finer grind. Now I have the problem of having to back off as the grind is too fine - a problem Im glad to have

    The grind is nice and consistent too - no more speckles of "bits" through the coffee.  Though Ive been introduced to clumping now - cant win them all.

    cheers all.

       - Kevin

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  • Thundergod
    replied
    Re: Iberital challenge not grinding fine enough - burr alignment?

    Originally posted by 6C62716E69626B77070 link=1234397240/6#6 date=1234609369
    Might need to invest in some earplugs
    $1 a pair at my local chemist.

    Leave a comment:


  • kevinelp
    replied
    Re: Iberital challenge not grinding fine enough - burr alignment?

    After some more tinkering, I cant really see anything wrong. Im starting to think this wailing banshee is normal for the species. I would have thought the grinder would be silent (bar motor noise) with no beans in the grinder (it is when dialed really coarse for plunger), but with it dialed fine to espresso levels it makes noticeably more noise.

    Might need to invest in some earplugs....

      - Kevin

    Leave a comment:


  • beanflying
    replied
    Re: Iberital challenge not grinding fine enough - burr alignment?

    Might also be possible it has been fed a rock at some stage of its life When you have it stripped down run it and have a close look at the shaft for any movement (KEEP FINGERS OUT OF THE WAY ) Also with it turned off see if there is any freeplay in the shaft (signs of bearing wear).

    Leave a comment:


  • kevinelp
    replied
    Re: Iberital challenge not grinding fine enough - burr alignment?

    Hmm, pulled it apart again this morning before work. Found that if I put pressure on the top burr carrier towards the rear of the grinder, the noise goes away, pressure towards the front makes it louder. I put a couple layers of teflon tape to hold the top carrier a little more firmly in place, seemed to improve it slightly.

    Given the noise is cyclic with rpm, I suspect the lower burr is ever so slightly eccentric, combined with slightly less that perfect centering of the burrs. The noise goes away while grinding beans, but returns when they are exhausted. Guess the manufacturing tolerances are not perfect - somewhat expected.

    Good news is that the grind is getting pretty close to dialed in now - no more inverted water fountains, so at least the grinder is usable, albeit a little noisy.

    I might try loosening the nut holding  the lower burr and re-tightening - might just change the centering enough to eliminate the noise. Could be tricky - not clear how to get any purchase on the shaft to undo the nut.

    Either way, Im getting my caffeine dose now, so life cant be too bad  

    cheers
       - Kevin

    Leave a comment:


  • kevinelp
    replied
    Re: Iberital challenge not grinding fine enough - burr alignment?

    Hi All,

    I pulled it apart tonight and it, yes it was full of old coffee grinds.

    After cleaning it, and inspecting (no visible damage that I could discern), I put the top burr and carrier back in, together with the worm screw and ran it. I kept tweaking it finer and finer until I could hear metal on metal rubbing, and then unwound it just a touch. This should be the finest it goes. Ill give it a whirl tomorrow morning and see how it performs.

    One issue I noticed though, was that when I put the top cover and hopper back on, a metallic rubbing/squeaking had returned. As if the carrier had moved and one side of the burrs was now making contact. Not sure how this could happen - the top burr and carrier seemed a tight fit in the holder.

    Will play with it more on the weekend if I still cant get it fine enough.

    Thanks for the tips.

    Leave a comment:


  • blanyon
    replied
    Re: Iberital challenge not grinding fine enough - burr alignment?

    Could be blunt burrs? Are they relatively new, any history of use?

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  • beanflying
    replied
    Re: Iberital challenge not grinding fine enough - burr alignment?

    Hi Kevin,

    I used to own one seemed to periodically glug up with fines around the sweeper vanes below the burrs this in turn partially filled the outlet chute and caused consistancy issues. If you havent already then a really good clean might be a good place to start. You will find that there is no provision for re-aligning the burrs other than screwing them in or out either.

    My curent Ascaso shares the same issues and burr set as the IC (only used for Syphon or Plunger) and while it makes ok espresso grinds my big commercial one is much much better

    good luck.

    Leave a comment:


  • Iberital challenge not grinding fine enough - burr alignment?

    Hi all,

    Ive just picked up a second-hand Iberital challenge. Ive got sick of grinding for Silvia with my Zass.

    However, seems the challenge wont grind fine enough for Silvia, something I know it should be able to do.

    Ive adjusted to the point where the burrs are just rubbing and backed off just a touch (about half a turn, maybe more), but the grind is not fine enough. With my Zass, I actually do have the burrs slightly rubbing, but I did not expect the challenge to be the same give the speed of the burrs, and more solid construction.

    I suspect the burrs are not perfectly aligned, but have not got round to tinkering yet. Im hoping it can be adjusted via disassembling  and reassembling so that the alignment is better - assuming that is my problem.

    Guess the coarse grind could be symptomatic of burr damage also?

    Any words of wisdom from challenge owners, or anybody else, before I start tinkering?

    Thanks in advance

       - Kevin

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