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Thread: Disassembly of Bezzera BB95 grinder

  1. #1
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    Disassembly of Bezzera BB95 grinder

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Im restoring a Bezzera BB95 grinder that appears to have been cleaned never. It smells like a dogs bum. Actually slightly worse I think.

    Ive managed to pull apart the doser and give it a good scrub out (including removing a spiders nest and some dead cockies).

    For the grinder itself I think I need to remove the burr assembly from the drive shaft, as shining a torch up the chute I can see lots of coffee tar on the underside of the brass thingamy. After scraping as much crap as possible off its still pretty gross.

    The three screws holding the burr came out easy enough, but it wont budge. Not sure if its just a tight fit, or if the tar has glued it in. What Id like to do is remove the entire brass do-hickey as well. I can see that its threaded on but how do you unscrew it? I cant find an easy way to prevent the motor shaft turning.

    My next attack will be to pull the cover off completely but I thought Id ask first if that were necessary. Ive included a hopeless phone-cam shot showing the burr assembly with the 3 screws removed. Inside the brass bit sticking up in the centre you can see that its threaded onto the drive shaft.


  2. #2
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    Hi Crufty,
    I realise that this post is years old, but I am in the same situation, having just purchased a secondhand BB95 grinder.


    I've pulled it to bits but am stuck at the same juncture as you.
    - I have undone the screws and the burr is removed, but would like to know if its possible to remove the brass bit from below (the parts manual calls is a "fan")

    Parts manual is here: http://coffeesnobs.com.au/documentat...s-diagram.html

    On the off chance that you receive an alert for this (thread reply), and that you were able to sort it out please let me know, if anybody else knows how to remove the "fan" please feel free to let me know too



    cheers!

  3. #3
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    cheesel,
    Having dealt with grinders,both domestic and commercial,the majority of drive connections (blade/burr) are usually left hand thread (motor shaft). This allows quick and easy connection of items fitting together ,with a removal requiring a clockwise rotation (with shaft fixed) .
    See how you go with that option,looking at the parts break down,there isn't any visible provision to lock the blade/burr onto the shaft.
    Good luck,
    Cheer's,
    Mick.

  4. #4
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    Hi Mick,
    Thanks for the reply. I could not find any way of locking the shaft (there is a rubber cap at the other end that I though might hide a slot that would allow a screwdriver to lock the shaft, alas it has no slot).
    I pulled the motor out of the machine to check if there was anything that I could not see, there was not.


    In the end, I just made a bit of a paste of espresso cleaner and used a toothbrush to scrub it well.
    Its not 100% clean, but probably 99% clean and 1000 times better than my starting point.


    I have put it all back together, I need to purchase new burrs but am about to trundle off to the shops to get some beans.
    (this is my first ever grinder).


    Cheers, Chris.

  5. #5
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    Some pics...
    Attached Images Attached Images

  6. #6
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    cheezel,
    See you discovered there's more then one way to ..........a cat!
    Next time you have the grinder apart and the motor rotor/shaft out,try gripping the whole thing in a vise,using wooden(ply) pieces rather then the steel jaws to grip the aluminum rotor (AC or commutator DC universal) assembly.
    Once safely and securely held ,the fan/burr base should be able to be rotated clockwise and removed for replacement or cleaning.
    Merry Christmas & happy 2016,
    Cheer's ,
    Mick.

  7. #7
    Mal Dimal's Avatar
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    Sometimes these things are also pressed on after the part has been heated, then shrinks to a tight fit on the shaft when cooled...

    Mal.

  8. #8
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    Thanks Mick & Mal for the info.
    I suspect I wont be pulling the shaft out of the housing any time soon, seems a bit overkill that this would be required, but seems to be the case.

    Re: Screwed vs pressed, there is a thread cut inside of the brass "fan" so I think its screwed on. I did read of another brand that was pressed though. Unsure if service manuals for these exist, none that I could find in about 10 mins of searching under bezzera BB95 or bregant junior etc. Id be surprised Tha the shaft could not be locked without removal but if possible it was not apparent to me..

    Anywho, happy for now, grinder is clean and tomorrows French press will come from it.

    Assuming all seems aok, need to work out a budget for a half decent espresso machine

    Cheers all and merry Christmas too.

    Ta, Chris.
    Dimal likes this.

  9. #9
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    It’s a bit drastic, but I have just acquired two Bezzera BB90 Grinders that needed disassembling to clean and replace the bearings.

    With a lifter under the fan and gently tapping on the loosened nut the first one came off with minor damage to the thread.

    This method didn’t work with the second. I had to removed and dissembled the motor so I was just left with the armature held in the top housing by the fan. As I don’t have a press I gently hammered on the nut supporting the top housing on a large vice. The fan eventually came off but the thread on top of the armature was destroyed. Using a lathe I then tapped a 8mm thread into the tapered section of the armature shaft and installed a 8 mm stud. This part is now as good as new. With the correct gear this was easy to do and I’ll do the same to the other unit.

    Overall I’m very impressed by the quality of the engineering and I’ll probably rehouse the grinder section into a new housing and convert the grinder into a low profile on demand electronic doser. I suspect it will have a very low retention making it ideal for home use.

  10. #10
    Mal Dimal's Avatar
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    Quote Originally Posted by greg-g View Post
    Using a lathe I then tapped a 8mm thread into the tapered section of the armature shaft and installed a 8 mm stud.
    Out of interest, was the original thread L/H or R/H?
    Will be important, to ensure "unwinding" doesn't occur through normal operation...

    Mal.

  11. #11
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    The original thread is a standard 8mm 1.25 pitch R/H thread.
    The burrs are described as Left hence I assume the motor rotates anti clockwise
    Now I've had everything apart I'll make a proper puller for future dissasembly
    Dimal likes this.



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