civ wrote:The plunger will move under it's own weight and have a recess in the end to accomodate the spinning nut so that by the time the borders of the plunger's end touch the upper carrier, all the beans will have been pushed into the burrs.

This is probably not necessary and possibly a bad idea if not well executed.



I have a mini hopper like this on the Macap MC4 and MXK. When the beans run out, the plunger spins a bit on the nut, but not too much. If you add a recess it should be concave so there is no possibility of a bean jamming between the plunger and the spinning nut.

The hoppers are held in place with M5 grub screws. Don't over tighten or the plex tube will crack.

Hello again:

Ken, Marshall, Ian ...

I would like to apologise to you all for my not being as clear as I should have been with respect to how I am pulling shots at this time. My fault, I should know by now that trying to do two things at the same time can be problematic at best.

The thing is that I'm not using the Max at this time, the main causes being the hopper and the doser. I have taken it apart to clean and am studying the mods I want to implement during whatever time I can devote to that.

What I am using is a hand mill, both for what I pull on my Pavoni EP and my Cimbali Junior D/1. And it's a C.A. Lehnartz and not a KyM, which is patiently awaiting it's hand lacquer job.

I don't weigh the beans: I just fill the little bugger up to the brim, flip the lid, make sure the drawer is in place (yes, I have missed that detail once or twice) and grind away. I finally found the right place for the adjustment lever so my shots are reasonably good. A full receptacle can get me the ~ 30 grams I need for my two morning lattes.

Marshall wrote:How does that work exactly?
How much excess do you wind up throwing out?

With the Lehnartz, nothing. Just what I spill if I'm sleepy.
When I get the Max working I'll see. Hope that got cleared up.
Sorry Marshall, my fault.

Ken Fox wrote:... I can tell you how I do it.
... develop a sense of how long to leave the grinder on.

I agree.

I do exactly the same as you but I use a styrofoam cup instead of a ramekin to weigh the grinds with a cheap scale and use a part of a yogourt cup to fill the portafilter. I tare, fill, weigh and then do the WDT inside the styrofoam cup. It works great but then I have to say that there's almost no clumping with the Lehnartz.

cafeIKE wrote:... probably not necessary and possibly a bad idea if not well executed.

The tube I describe is almost exactly as what your photo shows. It will be a bit longer so as to be able to use a longer plunger, the longer it is the less likely it is to jam inside the tube. It will be made either from dense wood or metal so as to be heavy enough on it's own.

cafeIKE wrote:... the plunger spins a bit on the nut, but not too much.
... recess it should be concave so there is no possibility of a bean jamming ...

Indeed ...
The end of the plunger will of course have a concave recess just the right size so that beans cannot jam between the sides of the nut and the plunger. In theory the plunger will not come into contact with the nut so it should not spin at all. But if it does spin, it will be due to a bean or two caught between the top of the nut and the end of the concave recess. Then I'll know right away that the coffee has run out. =-)

The idea of the tube is to keep "popcorning down" while single dosing, grinding as constant as possible and this from happening:


Photo by Jeff Sawdy

It should fit on in place of the original hopper in a way similar to this:


Drawing by Mats Leidö

Thank you all for you input.

Cheers,

CIV

civ wrote:It will be made either from dense wood or metal so as to be heavy enough on it's own.

The bean column above the burrs is very short on a Cimbali. See La Cimbali : Finger Guard or Bean Mass Regulator

On the MC4 and MXK I did quite a bit of messing about with the 'bean load' weights, finally settling on ~70g for the MC4 and ~110g for the MXK

I bought my Junior from Chris back in March and love it. I did some mod's with it like the throat extension and removed the finger guard, since I grind enough beans for two doubles. Have no problems with it pop corning. Made the throat extension out of a 1 1/2" pvc male adapter so the beans go straight into the burrs. Found the mod on this site, I just wish the grind adjustment knob was on the side like it is on the Max instead of the front.

Update to the OP:

While disassembling the Max to see about the possibilities of converting it to doserless while at the same time using the doser's 'body' to that effect, I found that the drawing I posted (original © cafeparts.com) did not include the doser's mechanism cast Al shell, an essential part towards achieving the project as it holds the acrylic cylinder in place against the chamber's chute and receives the ground coffee. A new drawing has been posted to correct this.

All in all, the only parts that have to be removed from the doser are just those that belong to the inner mechanism. It's all easy enough to take apart and put together again if the necessary precautions are taken.

The challenge now is the design of a funnel to receive the grounds and send them to the exit hole.

Cheers,

CIV

I have a La Cimbali Cadet, which I believe has the same doser as the Max. What I did was remove the flap at the top of the doser to allow access to the grind chamber exit chute. I normally grind per shot, and to remove the remaining grinds in the exit chute I apply a few puffs with a hand "pump/blower". To keep the tip of the blower away from the burrs I stuck a length of wire into the tube an inch from the tip

The first two things I did was remove the auto grind flapper from the hopper and put a feed tube in the throat of the grinder to keep beans from sitting around on the burr carrier shelf. Have not needed to make any change since that. She works super as is. I use a small round mushroom brush to brush out the chute after grinding and give it a 3 second pulse before I start grinding to purge anything still in there. I have had no desire to upgrade the grinder for a couple years now.

Hello all:

Before I continue with this post, I'd like to say something: I have a Cimbali Max because I purchased it, paired with a Cimbali Junior D/1, both in almost new condition and for a very low price, ~20% less than what a Rancilio Silvia V3 costs today in the US.

Quite evidently, a once in a lifetime oportunity.

Had I been able to choose, I would have undoubtedly chosen a Cimbali / Aurora single lever and a doserless grinder which could be used without a hopper. But it was not the case as imported espresso equipment of this quality is very scarce in AR and when available, in so-so shape and quite expensive, as well as any available parts.

That said, I am aware that the object of my present ramblings are to try to be able to do what I want (double dose grind, no waste and no hopper or doser) with what I have (a Cimbali Max with a huge hopper, a tendency to 'pop-corn' and a non-removable doser).

Not an easy task, difficulties and contradictions abound as the Max was designed for different type of regime and environment, but it's what I have to work with.

And I'm very happy with it. =-)

---

From previous observations, I have am convinced that grind retention inside the exit chute is (IMO, of course) the main or at least one of the main problems that affect grinders with burrs on a vertical axis, flat or combination conical/flat. My idea is that the combination of carrier vane design and exit chute length are the culprits as they do not address the change of direction the grinds need, basically a 90° turn downwards. But that's just 'my' idea.

In any case, this topic has been discussed to a certain length here:
Lower burr carrier design for reduced clumping

I have disassembled the Max's doser mechanism as explained in my previous posts and been able to see exactly how the grind falls from the exit chute into the doser cavity, only to find that it is no exception: the Max grinds faster than what it can send/throw/push/extrude or whatever the grinds towards the doser cavity and the grind piles up inside the exit chute.

So I'd say that this is probably the first (and main) problem to overcome. If this could be solved adequately, I think the rest, getting the grind to the PF in single doses, may be much easier to achieve.

There is no possibility of making any mods to the Max's grinding chamber/carrier vanes. And even though the vanes rotate very closely to the chamber walls, (much like the Barazza Vario), the ground coffee still piles up inside the (apparently much longer) exit chute and is pushed forward as the grinding continues.

From the thread mentioned above:

shadowfax wrote:The Vario seems to keep its retention at next to nothing by making the grind chamber hug the burrset as tightly as possible
... I think the design defeats the clumping inasmuch as the chute is so narrow ...

Lowering the feed volume could solve part of the problem as the grind will not pile up in the exit chute but the lack of a column above the conical/flat burr set will generate popcorning and apparently there's also the possibilty of static generation.

yoonkk wrote:... and to remove the remaining grinds in the exit chute I apply a few puffs with a hand "pump/blower".

I find this to be an interesting idea but it entails blowing air in the direction the grinds come from.

I have done it with other (smaller) grinders I have and now tried it with the Max: blowing air (basic, blowing through a 55 mm tube stuck over the burrs) from where the beans are fed once the grinder stopped and I've found that it works really well, leaving very little behind.

ie: Applying positive air pressure in the direction the grind is going, towards the doser chamber.

If positive air pressure could be applied during the grinding process (and not after) it may well be that much less pressure will be needed to move along the grind and keep the chute empty. ie: a small amount of grinds are easier to move along than a pile-up or important accumulation of them.

I have not thought about how this could be done yet, but I'd appreciate any comments.

Cheers,

CIV

civ wrote:Hello all:

Before I continue with this post, I'd like to say something: I have a Cimbali Max because I purchased it, paired with a Cimbali Junior D/1, both in almost new condition and for a very low price, ~20% less than what a Rancilio Silvia V3 costs today in the US.

Quite evidently, a once in a lifetime oportunity.

Had I been able to choose, I would have undoubtedly chosen a Cimbali / Aurora single lever and a doserless grinder which could be used without a hopper. But it was not the case as imported espresso equipment of this quality is very scarce in AR and when available, in so-so shape and quite expensive, as well as any available parts.

That said, I am aware that the object of my present ramblings are to try to be able to do what I want (double dose grind, no waste and no hopper or doser) with what I have (a Cimbali Max with a huge hopper, a tendency to 'pop-corn' and a non-removable doser).

Not an easy task, difficulties and contradictions abound as the Max was designed for different type of regime and environment, but it's what I have to work with.

And I'm very happy with it. =-)

---

From previous observations, I have am convinced that grind retention inside the exit chute is (IMO, of course) the main or at least one of the main problems that affect grinders with burrs on a vertical axis, flat or combination conical/flat. My idea is that the combination of carrier vane design and exit chute length are the culprits as they do not address the change of direction the grinds need, basically a 90° turn downwards. But that's just 'my' idea.

In any case, this topic has been discussed to a certain length here:
Lower burr carrier design for reduced clumping

I have disassembled the Max's doser mechanism as explained in my previous posts and been able to see exactly how the grind falls from the exit chute into the doser cavity, only to find that it is no exception: the Max grinds faster than what it can send/throw/push/extrude or whatever the grinds towards the doser cavity and the grind piles up inside the exit chute.

So I'd say that this is probably the first (and main) problem to overcome. If this could be solved adequately, I think the rest, getting the grind to the PF in single doses, may be much easier to achieve.

There is no possibility of making any mods to the Max's grinding chamber/carrier vanes. And even though the vanes rotate very closely to the chamber walls, (much like the Barazza Vario), the ground coffee still piles up inside the (apparently much longer) exit chute and is pushed forward as the grinding continues.

From the thread mentioned above:

I find this to be an interesting idea but it entails blowing air in the direction the grinds come from.

I have done it with other (smaller) grinders I have and now tried it with the Max: blowing air (basic, blowing through a 55 mm tube stuck over the burrs) from where the beans are fed once the grinder stopped and I've found that it works really well, leaving very little behind.

ie: Applying positive air pressure in the direction the grind is going, towards the doser chamber.

If positive air pressure could be applied during the grinding process (and not after) it may well be that much less pressure will be needed to move along the grind and keep the chute empty. ie: a small amount of grinds are easier to move along than a pile-up or important accumulation of them.

I have not thought about how this could be done yet, but I'd appreciate any comments.

Cheers,

CIV

Hi,

Excuse me for quoting your entire post, but I couldn't figure out easy criteria for selecting a part of it. My interpretation, to be honest, is that you have a solution in search of a problem.

The Cimbali Max grinder does have some "warts" in home usage, as does almost any commercial grinder that one tries to use in the home. If one were to make a list of these limitations, the doser would not be high on the list. In fact, the doser is a pretty good doser and it does what it is supposed to do, i.e. to get the ground coffee from the grind chamber into the PF, preserving the ground quality of the coffee while not making much of a mess or being hard to clean. To the extent that it is limited, one can remove the doser flap/door easily, and then use an implement like a chop stick to clean out the doser chute after each grind period. Modified in this way, and with the grind path the machine possesses, this commercial-quality titan level grinder produces excellent quality grinds with relatively little coffee waste.

As to the popcorning/reduced grind quality when the grinder is not operated with enough beans in the hopper, there are simple solutions to that which have been posted here several times, which although not perfect would certainly improve things without going to much effort.

Certainly, you are free to spend time modifying equipment as you would like, and far be it from me to try to tell you not to work on this "project." But it is my opinion that if your goal is to improve your espresso quality, to reduce waste, or to solve any pressing problem with this grinder, that you are really and truly wasting your time.

Good luck.

ken

I agree with Ken. The various design features of this grinder, as with all quality espresso grinders, are there to make it easier for baristas to do a quality job of brewing espresso. Removing them is as likely to generate new problems as to solve old ones.

Once you've been using the grinder for a while and have identified genuine and specific complaints or problems, that's the time to exercise cleverness and implement changes (though I can't imagine any serious problems on this grinder where the best solution is elimination of the doser).