Feca wrote:This is precisely why I backed out of my crowd funding order months ago, don't trust the long shaft design. I hope it works for everyone who got one though, I just would be constantly doubting whether the shaft is centered/straight or not!

While I'm not an engineer, I really struggle with this argument. There are hundreds, if not thousands of HG-1s and Versalabs M4s in the wild that use a long shaft design, and yet there aren't dozens of complaints about bent shafts, alignment problems, or quality in the cup issues.

I feel like this argument was made up by a bunch of conceptual engineers who could see a *possible* design flaw and improvement, and they may even have a particle distribution graph showing how things have changed. Combine it with a couple of loud anecdotes of a broken grinder. Yet absolutely no categorical proof that the machine is compromised, or that the espresso or brewed coffee is materially impacted.

You could argue that the Kafatek MC4 is better (I have a Max and enjoy it immensely), but even Denis himself won't reveal the results of a particle distribution graph on his own grinders, and has repeatedly said that the doesn't believe that the science there is proven. Weber has said similar things. What Denis HAS said, which benefits his bottom line, is that he doesn't like the long shaft design. But with no documented proof as to why his design is better outside of the conceptual realm.

I am an engineer, and there is no doubt that a longer shaft is a disadvantage for accuracy. It's just a disadvantage.
As for the particle size distribution, I think people are a little too concerned about it since the graphs and such were published when the EK43 was in the limelight.
To be honest, for a product that costs several thousand dollars, there is a huge variation in individual products, and the way the beans are dosed can also change the particle size significantly.
Even if you measure the particle size distribution of one individual, it is meaningless because it is the particle size distribution of that one individual.
A multi-thousand dollar grinder is cheap when you think of it as a machine.
Unless you have a problem that prevents you from grinding espresso, enjoy the taste and personality of the grinder you own.

I'm using a translation tool, sorry for my bad English.

I'm sorry.
I'll correct my earlier words.

The correct phrase is "the longer the shaft, the more likely it is that the accuracy will be compromised.
Of course, if you are looking for higher machining accuracy, you will have less centering shake than a shorter shaft with lower machining accuracy.
However, at the price point of this inexpensive machine, it would be unreasonable to ask for that much.
In the first place, I wonder if the hole in the Mazzer's conical burrs is really in the center...

Same could be said for all other burr manufacturers...

My original HG-One (with stepless adjustment) has the same shaft design as the later HG-1, HG-2 and now this KEY. I'm sure most shafts are very precise and straight. But saying they all are is just not true, because I can see mine visually wobbling with the naked eye, even my wife who is not technical or interested in these things can see it wobbling. It has always been like this. They promised high precision when they made the first HG-One, they promised it with every subsequent version. Maybe they didn't QC the first versions and now they do, but all I'm saying is that it can happen and I can taste it's detrimental effect on the extraction. When looking down the burrs I can see the gap wobbling wider, then narrower when turning. No amount of alignment can help, because it's just not turning round (as you can understand). Maybe all new HG's and KEY get excellent QC and subsequently perfect straight shafts, but I'm just mentioning my concern. Brush it off all you want (just theory etc) but in my case there are so many fines produced that the extraction just tastes burnt, no matter what I try, and I've tried for almost 9 years, using five different lever machines, with temperature control (Caravel with PID +\- 0.1°C) and all the techniques discussed here at HB over the years. My Rosco hand grinder produces less fines and therefore tastes better objectively, even my wife always likes the results better without knowing (if I bring her a coffee without telling). So you can make fun of me all you want about nitpicking and alignment being a fringe, useless business, but then why are there such 5k grinders? If your regular Hario should be good enough? Producing many fines.

In my eyes the long shaft should have been constrained at the bottom somehow. But I fully agree if it was always completely straight (good QC) it should be fine and most probably are, maybe I'm just the only unlucky one.

Edit: to clarify, I can visually SEE the end of the shaft wobbling. First I thought the hole in the lower burr was not centered, but when I took it off and just looked at the shaft wile turning, it's the shaft. There is no movement in the shaft, that is, the bearings are solid and the construction is very strong, just a pity it's bent and has always been, since if it was straight from the factory but got bent while grinding coffee that would be even more worrying.

Also, I looked at the grinds produced under a microscope and compared it to my other grinders, this one definitely has way more fines.

I've heard conicals are less sensitive to alignment, but too much fines can really destroy extraction apparently.

I'm not trying to bash the KEY or the HG's I'm just voicing my concern and asking if I'm (hopefully) alone with this issue and what it done to prevent it (apparently better QC now).

Hugonl28 wrote:But saying they all are is just not true, because I can see mine visually wobbling with the naked eye, even my wife who is not technical or interested in these things can see it wobbling. It has always been like this.

...

a pity it's bent and has always been, since if it was straight from the factory but got bent while grinding coffee that would be even more worrying.

I do not deny your experience, or the few others who have said similar things. But to clarify, you knew since Day 1 that your product was defective, and didn't exchange or return it? Did you reach out to Lyn/Weber back in the day? Why keep a grinder for years and years if it stinks?

I'm struggling to see how your anecdotal experience of receiving a lemon is now an indictment of the entire product or design process. Every product manufacturer produces lemons. The issue I've raised is whether 1) there is something systemically broken with a long shaft, resulting is structural problems affecting hundreds of owners, or 2) there is a conceptual improvement to be made to a long shaft, yet in reality 99% of the customers have great, high performing grinders.

MOTOKI000 wrote:I am an engineer, and there is no doubt that a longer shaft is a disadvantage for accuracy. It's just a disadvantage.

Your comment (trimmed for readability) is very helpful, thanks. Translation is fine.

Auctor wrote:I do not deny your experience, or the few others who have said similar things. But to clarify, you knew since Day 1 that your product was defective, and didn't exchange or return it? Did you reach out to Lyn/Weber back in the day? Why keep a grinder for years and years if it stinks?

I didn't know since day one. It was my first high-end grinder (previously had Eureka Mignon). For a few years I used it and just assumed it was correctly aligned from the factory. Only after a thorough maintenance checkup and doing a re-align did I notice it was impossible to align since the shaft was bent. I assume it's always been bent. Grinding beens can't bend it right? It has never left it's place on the table. I always made espresso with this grinder and had no direct comparison, so didn't notice the burnt taste. Though did find my friends E61 + Vario better tasting.

Traveling I've always made espresso with my Portaspresso + Rosco grinder, never used the Rosco with my Strega, Caravel, Pavoni etc. Always found the Portaspresso + Rosco tasted better than what my HG-One produced, but never understood why, till I did a thorough examination with blind tasting using my wife and friends. I didn't think alignment would be such an issue, for me low retention and easy grinding (and sturdy, long lasting design) was the main reason I went with the HG-One, but just assumed it would be accurately built.

To be clear, I'm not angry or disappointed, I understand these things happen with manufacturing. Yes, if I'd noticed in the first year I'd have contacted the manufacturers. Now it's too late anyway and to be honest after almost 9 years of grinding it was a good service life (albeit could have been better if shaft was straight). I did enjoy every single cup it made, but now knowing how much better an espresso with less fines can taste, I can't enjoy it that much anymore. Ignorance is bliss I guess

The only reason I ask here, is I don't want to get burnt twice, so just trying to gauge if this is a recurring issue, or really like you say, just one unit. Actually if it's only me, then that's pretty impressive. But I do stand with my opinion that a shorter shaft seems less likely to wobble that much at the end of the shaft. If it's straight, jup, that's probably fine, no matter how long, we're just talking about chances here. I love the design of Weber, I will happily buy one of their products again (probably KEY or save up for EG-1).

Just to reiterate: only asking here if it's happened often that the shaft is not straight, that's a legitimate question right, for such an expensive grinder? I have tried to search HB but couldn't find much. Honestly I haven't visited HB for years since I was just enjoying my coffee, only recently has the thought arised to upgrade my grinder and was looking for an electric one, after years of handcranking

Hugonl28 wrote:Edit: to clarify, I can visually SEE the end of the shaft wobbling. First I thought the hole in the lower burr was not centered, but when I took it off and just looked at the shaft wile turning, it's the shaft. There is no movement in the shaft, that is, the bearings are solid and the construction is very strong, just a pity it's bent and has always been, since if it was straight from the factory but got bent while grinding coffee that would be even more worrying.

Did you measure TIR (total indicator runout) and send to Weber? Maybe the shipping company dropped the grinder during delivery?

Hugonl28 wrote:To be clear, I'm not angry or disappointed, I understand these things happen with manufacturing. Yes, if I'd noticed in the first year I'd have contacted the manufacturers. Now it's too late anyway and to be honest after almost 9 years of grinding it was a good service life (albeit could have been better if shaft was straight). I did enjoy every single cup it made, but now knowing how much better an espresso with less fines can taste, I can't enjoy it that much anymore. Ignorance is bliss I guess

I would offer that it can't hurt to contact Douglas and ask. He may tell you that they no longer have parts for your grinder or he may be able to offer a solution. It's worth trying as you have nothing to lose. I've not had any problems with any of the Weber products that I own, so I can't personally vouch for how they fix or service their grinders. I can tell you that whenever I've reached out to Weber with questions, I've always gotten timely responses, many of which were directly from Douglas himself.