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Improving Mazzer doser efficiency

Postby HB on Tue May 20, 2008 8:12 pm

AndyS showed us How to Tame a Messy Mazzer Doser and Teme showed us how to improve the Mazzer Mini doser sweep efficiency. Below are the modification steps I documented years ago on CoffeeGeek for sweeping the doser vanes clean.

Materials:

  1. PVC to NPT adapter (2" inner diameter)
  2. 2" flat washer
  3. 8mm nut
  4. 2" hole cover (for desks / countertops)
  5. 7 ounce kid's cup.

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And not shown above:

  • 1" brush w/wooden handle
  • 1" angle bracket w/small machine screw
  • Sticky-back velcro or ordinary electrical tape.
Total cost is around $4 and I bought everything (except the kid's cup) at Ace Hardware. It's a lot easier to find stuff there than Home Depot when you need a bunch of onesy-twosy items like this. I chose the washer and hole cover setup for when I want to switch from single shot to multiple shots. Just remove the cup and grind 3-4 shots, i.e., it pretty much works like before.

Modification Steps:

Below is the brush assembly. I found it was a tight fit with a 1" brush, but I didn't see any 3/4" brushes (1/2" is too small). It's at a slight angle to compensate. This picture shows the doser without the adjustable sweep vane in place. I folded over strips of electrical tape halfway lengthwise and attached them to every other vane, extending them about 1/8" inch.

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Now the PVC adapter piece, washer, 8mm nut, and cover are in place. Since there is a small raised bevel on the top of the sweep vane, I had to trim a little from the inner edge of the hole in the PVC adapter with a utility knife. With the washer and nut in place, it sits nicely on-center and doesn't budge.

NB: I would have reused the stock nut, but it was too tall to allow the 2" hole cover to fit.

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The finished modification. A few grounds might stick to the cup so I remove it and toss it in the dishwasher once a week, then choose another. This also give me the chance to pick a color based on my mood. :-)

There's a lot less space with the cup in place, so you can't grind 4-6 shots at a whack. With the cup removed, the grinds shoot over the top of the PVC adapter. I rarely use this option, but it is nice to clean up by just popping in a new cup.

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For sake of completeness, my rendition of Teme's sweep mod:

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Quite simply attach the tape / velcro to the upper part of the vane (the one that moves up and down). With these two modifications and a quick swish of the exit chute, you'll recover nearly all the coffee grounds.
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Postby HB on Wed May 21, 2008 8:34 pm

Below is a similar modification from Chris to prevent grounds from collecting on the center ledge of the doser vanes, copied from Oily beans, how to clean the hopper? for easy reference. Also see Teme's Mazzer mod no.4 - the inverted cup.

Psyd wrote:Ya need to get the larger egg, and use the taller part of the egg, preferably. Once I have the grinder apart, I just take the upper star and heat it gently with a bit of a gas stove flame, and then set it on a flat surface. I rest the egg on it, careful to center it, and let it mold itself to the star and come to a rest against the flat surface. Clean up the parts that spooge out with a razor knife. You want to be careful not to get the star too hot, use common sense when using hot things (they burn and put out noxious fumes) well ventilated area, and all the other caveats that go along with hot and sharp things, and think about having a couple of eggs to experiment with.
The downside is that it isn't really 'removable'. To get the star on and off, the egg has to be out of the way. To solve that, I've been using a 'gorilla glue' that covers the gaps and holds the egg on, but will come off without too much effort, and will clean off both surfaces easily.
I'm contemplating having a regulator knob (the knurled nut that holds the star assembly on) made in the shape of the egg, or maybe a cone. Anyone with metal shop toys?

Since I had the boys apart for cleaning recently, and the decaf Major isn't all back together yet, I've got this lying around the kitchen.

Image
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Postby hbuchtel on Thu May 22, 2008 11:06 pm

Similar to the mods above, I removed everything above the lowermost star/vanes and attached a small plastic cup to the threaded post in the middle of the doser.
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If the path from the burrs is empty grounds do fly on to the top, but those are easy to brush off.

With that flat "dose cutting" piece of metal removed the viability is much improved!

Henry
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Postby hbuchtel on Thu May 22, 2008 11:19 pm

Nice, I just found that the steel cover for that plastic cup (actually the lid of a insulated thermos) still fits! :D

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Ok, back to work... :(

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Postby Randy G. on Fri May 23, 2008 10:47 am

Personally, I find that the doser wipes fairly clean on its own. The real problem with my Kony is the amount of ground coffee that remains in the throat between the burrs and the doser.
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Postby Psyd on Fri May 23, 2008 4:24 pm

Next time you're at that Asian Market, buy a bag of those disposable chopsticks. It's the perfect two-ended grinder cleaning tool...
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Postby HB on Fri May 23, 2008 4:59 pm

Randy G. wrote:The real problem with my Kony is the amount of ground coffee that remains in the throat between the burrs and the doser.

Here's my tool of choice:

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Acid brushes from the paint store
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Postby RegulatorJohnson on Fri May 23, 2008 9:00 pm

Psyd wrote:Next time you're at that Asian Market, buy a bag of those disposable chopsticks. It's the perfect two-ended grinder cleaning tool...


yes it is!! and you can put it in a pencil sharpener to make a nice point that works great.
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Postby Randy G. on Thu Jun 05, 2008 1:01 pm

Looking over all the various "solutions" here for the Kony, some looked good. I don't have a problem with the doser. My removal of the flapper switch and deflection guard and setting the doser to dispense as little coffee as possible makes it quite usable, and the vanes sweep the bottom of the doser quite effectively. I will probably add some velcro to a vane or two to make them 100% effective, but up to this point I have not seen the need.

But none of the solutions addressed my main concern which is the amount of coffee that remains in the throat. A standard brush pushes as much coffee back into the throat as it removes, and the chopstick thing doesn't reach where it is really needed. So here's my solution:

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One end has a "hook" that acts as a rake to remove the majority of remaining coffee in the throat. The length of it is specific to allow its use while the grinder is running. Flipping the tool 180 degrees allows the use of the brush at the other end to remove the last remaining coffee in the throat. The "Z" bend keeps fingers clear of the edges of the doser.
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Postby JohnB. on Thu Jun 11, 2009 12:23 pm

While adding Velcro strips to 3 of the lower doser vanes on my Major I decided to modify the upper sweeper assy so grounds don't collect on the doser outlet cover plate.

First you need to remove the 2 screws shown here:
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Here you can see the cast ridge that acts as a spacer between the plate & upper sweeper:
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You want to file or block sand this ridge down until the remaining portion is approximately equal to the thickness of the cover plate. I'd advise doing a few trial fits with screws tightened down as you go as the sweeper will bind against the cover plate if you remove too much material.
With the gap between the sweeper & cover plate all but removed the combination of the thwacking vibes & the sweeper keeps the upper area clean. Combined with the Velcro mod the only brush work required after grinding/dosing is knocking the few remaining grounds out of the chute while dosing & the plastic "nose" piece mod is unnecessary.

To please my wife who has complained about the metallic thwacking noise of the returning doser handle I added this "silencing mod":
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I used a piece of hard rubber shaped on a grinding wheel & glued in place using 3M Super Emblem Adhesive. The doser is now MUCH quieter & the spacer eliminates some of the annoying free play from the handle assy.
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