Mazzer Robur modification - port exit chute?

Grinders are one of the keys to exceptional espresso. Discuss them here.
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Jacob

Postby Jacob » Aug 13, 2007, 3:57 pm

Port & Polish - or just polish?

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I'm about to make some sort of doserless mod on my Robur.
As you can see in the picture, the inside of the chute looks pretty rough and I'm planning to polish it up.
In order to reduce clumping I am very tempted to port it as well (keeping the original size and shape at the inner end and tapering it out to an enlarged exit-port).
This is an irreversible mod and I would love to here what you know and think of this before taking action on it.
Will it work? Has anyone actually tried it? Any thoughts?

Thanks
Jacob

Caffewerks

Postby Caffewerks » Aug 13, 2007, 5:42 pm

I've been meaning to do this ( Porting ) for some time. I say go for it and let us know the results. Chances are you will be given a bunch of reasons why you shouldn't but if I had listened to everyone that said it wouldn't work, I would be working at Sbux!

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cafeIKE

Postby cafeIKE » Aug 13, 2007, 5:58 pm

How about a couple of close-up photos of the 'chute'?

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Jacob

Postby Jacob » Aug 13, 2007, 7:28 pm

There will be before/after pictures.

terryz wrote:I've been meaning to do this ( Porting ) for some time.


From someone who knows his stuff - very encouraging 8)

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Randy G.

Postby Randy G. » Aug 13, 2007, 7:29 pm

If you are converting it to doserless I would just leave it and see how that works out before changing the design. Make some cardboard mock-up chutes and see what works best. For example, pointing the chute at a slight angle in the direction the coffee wants to go may do the job without modding the body.

Before you begin with the Dremel, I would make an accurate template to match the original opening so that if things go wrong down the line you can rebuild the original opening shape and size with some sheet metal and epoxy.
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Jacob

Postby Jacob » Aug 16, 2007, 7:59 pm

Randy G. wrote:... I would make an accurate template to match the original opening ...

I planned to use the doser as the perfect template :wink:

Randy G. wrote:Make some cardboard mock-up chutes and see what works best.

I have been playing around with Illy cans before and I did some more tests yesterday.
But I don't like the distribution-patterns that I get :evil:

Instead of a passive chute I might ad an active 'distributer' :shock:

My 2. post on CoffeeGeek was actually a picture of an active mini-chute test (unbalanced and an awful distribution-pattern).
But a wheel of vanes (say 12-24) and a chute that's doesn't taper so much :?
http://www.coffeegeek.com/forums/espresso/machines/235091#235091


So much for the doserless mod - let's ruin the template :twisted:

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Jacob

Postby Jacob » Aug 16, 2007, 9:13 pm

I extended the bottom of the hole in the doser by 5-6 millimeters, mounted it on the grinder and marked the dosers 'window' on the chute. Then everything was smoothed out as much as possible within the limitations of this window.
This was not enough to get rid of the corner (marked with a red circle on the first picture) and the drop is not steep enough to make any real difference in 'coffee transportation'.

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Jacob

Postby Jacob » Aug 18, 2007, 7:39 pm

Here is the tools used for the chute porting (note the tips which is wrapped in tape to protect the inside of the grinder):
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I also hooked up a digital darkroom timer to internal electronics. The timer powers up together with the grinder and runs the relay (not the entire grinder).

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Jacob

Postby Jacob » Aug 19, 2007, 9:22 am

After a couple of days of observation I would have to say that I'm not sure that this porting is a good idea (unless one also creates a very steep slope/drop which would work by gravity alone).


It's like the modified chute just fills up slower, as the grinds seams to try to find a way over the grinds in front until the chute is full. The result is more grinds in the larger modified chute when the grinder is cut off :roll:

Maybe static would be a thing to look out for to?
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