Just received my La Cimbali Junior after sitting on the fence too long and missing the incredible deal offered on two of them by Chris during the recent HB-anniversary sale. Oh well. When I amortize the price I paid over the number of years the Junior will last, I'm fine with what it cost me.

This last weekend was my first chance to play with it, and as others have already written, this is an incredible grinder. Being a tinkerer, I decided to take the hopper off and have a slightly better look at the burr and entry path for beans into the burrs. I came up with a feed-funnel idea that I've already implemented; it guarantees that no beans get hung up on the little ledge right before the burrs (I used a cycling water bottle which I cut down to give me a funnel which fits perfectly inside the throat).

While I had the hopper off, I plugged the grinder in and turned it on, then off, and noticed that, as the lower burr was slowly coming to a stop, it is not perfectly aligned with the upper burr, in a rotational sense. That is, it seems to wobble a bit relative to the upper, stationary, burr. My guess is that the mounting hole for the lower burr is larger than the motor shaft onto which it mounts, and that it was cinched into place while slightly out of alignment. (A bolt is used to secure the lower burr to the shaft.)

The grinder seems to grind very well in spite of the wobble, so I'm wondering if it's worth trying to correct... Though, if it grinds this well with the burrs slightly out of alignment, how good would it do if they were aligned?! Malachi, or anyone else who's gotten familiar with this grinder, as only a true geek can, I'd appreciate some insight.

Thank you!

RAS wrote:Just received my La Cimbali Junior after sitting on the fence too long and missing the incredible deal offered on two of them by Chris during the recent HB-anniversary sale. Oh well. When I amortize the price I paid over the number of years the Junior will last, I'm fine with what it cost me.

This last weekend was my first chance to play with it, and as others have already written, this is an incredible grinder. Being a tinkerer, I decided to take the hopper off and have a slightly better look at the burr and entry path for beans into the burrs. I came up with a feed-funnel idea that I've already implemented; it guarantees that no beans get hung up on the little ledge right before the burrs (I used a cycling water bottle which I cut down to give me a funnel which fits perfectly inside the throat).

While I had the hopper off, I plugged the grinder in and turned it on, then off, and noticed that, as the lower burr was slowly coming to a stop, it is not perfectly aligned with the upper burr, in a rotational sense. That is, it seems to wobble a bit relative to the upper, stationary, burr. My guess is that the mounting hole for the lower burr is larger than the motor shaft onto which it mounts, and that it was cinched into place while slightly out of alignment. (A bolt is used to secure the lower burr to the shaft.)

The grinder seems to grind very well in spite of the wobble, so I'm wondering if it's worth trying to correct... Though, if it grinds this well with the burrs slightly out of alignment, how good would it do if they were aligned?! Malachi, or anyone else who's gotten familiar with this grinder, as only a true geek can, I'd appreciate some insight.

Thank you!

I think you need to confirm that it is really out of alignment, and what you are seeing is not an optical illusion. Also, you need to be sure when this condition exists; if it is just as the burrs are coming to a halt, it may have something to do with the design of the grinder, rather than it being a manufacturing fault.

Any company can make a manufacturing mistake, or any product can be damaged in shipping, however Cimbali does have very high standards on everything they put out with their name on it.

Greg Scace called me with a similar problem he had observed on a Junior grinder that he bought a couple of years ago; in the end he had it replaced. How he confirmed that in fact there was a problem and not just an erroneous observation, I'm not sure.

For the record, I have essentially three of these grinders, a ten year old Cadet (bought new) which is more or less the same thing, plus two current vintage Juniors. I've not had any problems with any of them.

With the information you have given us I don't think there would be any way that we could tell you what the difference would be if you got one that ground in a more "aligned" fashion.

For the record, grinding for espresso the burrs are pretty damn close together. If there was a significant problem with the alignment you would either get poorly and irregularly ground beans with inability to make fine adjustments, or you'd be hearing metal on metal grinding as the burrs hit at some point, or both. In the absence of those observations and if the grinds come out well and you have no problems with adjustability, my guess is that you have either an optical illusion or a design situation in how the grinder stops once the power is cut.

ken

Thanks for the reply Ken.

I really don't think what I'm seeing is an illusion of any kind. When the lower burr slows down enough that it's not a blurr, the lower burr appears to be shifted slightly, again, relative to the upper burr. It's shifted by maybe a millimeter, which is not much, but compared to my Tranquilo, in which the burrs are perfectly aligned, it is certainly noticeable. As I said earlier, the grind consistency is very good (there's just that nagging question about if it could be better).

One detail I forgot to pass along earlier is that I found the zero-point, which just so happened to be located right around 0.5 on the numbered scale, and at this point, there was a very slight burr-to-burr contact sound. The sound was very slight, and consistent sounding... though I'm not sure I'd notice what slightly misaligned burrs would sound like at 1600 RPM!

Again, I'm very happy so far, and I'd like to do what I do with any equipment: wring out every last ounce of performance by dialing-in every parameter I can affect.

Bob:

Ken and Dan's answers were both more academic than mine will be, but here goes-

My brother has a Junior grinder and we noticed the same thing, e.g. apparent burr wobble. To see if indeed this was a true problem we opened up the burr gap and fired her up. We then slowly closed the burr gap until a slight contact sound was heard. The soft contact sound was very uniform without any hint of being uneven or "wobbly".

So we chalked it up to something wrong with our perception rather than a fault with the grinder!

Glad to hear that mine is not the only Junior with this "issue"... if it really is an issue.

Dan, my observation, and concern, about the burr alignment is primarily due to what I've seen on other flat-burr grinders I've owned or played with. One of my other grinders is a Tranquilo, and the lower burr spins in perfect alignment relative to the upper burr. The lower burr is a completely smooth blurr at speed, and continues to be so when power is turned off - all the way until the burr comes to a stop.

Something I noticed last night when checking the Cimbali out a bit more is that the body of the grinder shakes slightly, much like a washer during the spin cycle with an unbalanced load, when it's winding down. The shake is subtle, but still noticeable. My theory is that this due to the lower burr's lack of symmetry.

I'm hoping someone with a Junior can give me some insight on how to reseat the lower burr. I'll probably drop a line to Chris and Roger at ChrisCoffee to see if they have some pointers. I'm an engineer, and tinkering is something I enjoy, so I'm ready to dive in... If there is a chance of improving this impressive grinder.

Thanks to all!

Ken Fox wrote:

RAS wrote:Just received my La Cimbali Junior after sitting on the fence too long and missing the incredible deal offered on two of them by Chris during the recent HB-anniversary sale. Oh well. When I amortize the price I paid over the number of years the Junior will last, I'm fine with what it cost me.

This last weekend was my first chance to play with it, and as others have already written, this is an incredible grinder. Being a tinkerer, I decided to take the hopper off and have a slightly better look at the burr and entry path for beans into the burrs. I came up with a feed-funnel idea that I've already implemented; it guarantees that no beans get hung up on the little ledge right before the burrs (I used a cycling water bottle which I cut down to give me a funnel which fits perfectly inside the throat).

While I had the hopper off, I plugged the grinder in and turned it on, then off, and noticed that, as the lower burr was slowly coming to a stop, it is not perfectly aligned with the upper burr, in a rotational sense. That is, it seems to wobble a bit relative to the upper, stationary, burr. My guess is that the mounting hole for the lower burr is larger than the motor shaft onto which it mounts, and that it was cinched into place while slightly out of alignment. (A bolt is used to secure the lower burr to the shaft.)

The grinder seems to grind very well in spite of the wobble, so I'm wondering if it's worth trying to correct... Though, if it grinds this well with the burrs slightly out of alignment, how good would it do if they were aligned?! Malachi, or anyone else who's gotten familiar with this grinder, as only a true geek can, I'd appreciate some insight.

Thank you!

I think you need to confirm that it is really out of alignment, and what you are seeing is not an optical illusion. Also, you need to be sure when this condition exists; if it is just as the burrs are coming to a halt, it may have something to do with the design of the grinder, rather than it being a manufacturing fault.

Any company can make a manufacturing mistake, or any product can be damaged in shipping, however Cimbali does have very high standards on everything they put out with their name on it.

Greg Scace called me with a similar problem he had observed on a Junior grinder that he bought a couple of years ago; in the end he had it replaced. How he confirmed that in fact there was a problem and not just an erroneous observation, I'm not sure.

For the record, I have essentially three of these grinders, a ten year old Cadet (bought new) which is more or less the same thing, plus two current vintage Juniors. I've not had any problems with any of them.

With the information you have given us I don't think there would be any way that we could tell you what the difference would be if you got one that ground in a more "aligned" fashion.

For the record, grinding for espresso the burrs are pretty damn close together. If there was a significant problem with the alignment you would either get poorly and irregularly ground beans with inability to make fine adjustments, or you'd be hearing metal on metal grinding as the burrs hit at some point, or both. In the absence of those observations and if the grinds come out well and you have no problems with adjustability, my guess is that you have either an optical illusion or a design situation in how the grinder stops once the power is cut.

ken

Hi:

I used a dial indicator to measure the runout on the one I returned. Its replacement also showed runout, but less than the first and I kept it, based on others' praise for the grinders. I forget how much runout either grinder exhibited. My Cimbali was an exemplary flat-burr grinder. I don't own it anymore as I have made the jump to conicals.

-Greg

PS - Ken, I just got back from a week in Nebraska. I'll get your thermofilter out this weekend.

k7qz wrote:Bob:

Ken and Dan's answers were both more academic than mine will be, but here goes-

My brother has a Junior grinder and we noticed the same thing, e.g. apparent burr wobble. To see if indeed this was a true problem we opened up the burr gap and fired her up. We then slowly closed the burr gap until a slight contact sound was heard. The soft contact sound was very uniform without any hint of being uneven or "wobbly".

So we chalked it up to something wrong with our perception rather than a fault with the grinder!

Actually this isn't a good test. The runout I've observed is runout in which the burr doesn't rotate on its centerline, but rather rotates off-center. This type of runout is measureable by removing the adjustable burr and then measuring with a dial indicator positioned on the outer circumference of the lower burr. The test that is described in the quotes text would only work if both the rotating and non-rotating burrs were misaligned so that the burrs had a "high spot" relative to each other. In the case of one burr exhibiting a high spot and the other perfectly aligned, the high spot would touch the perfectly aligned burr at even pressure throught the revolution of the burr, generating a constant note. This would also be the case for burrs which are parallel to each other, with the rotating burr exhibiting radial runout (the usual case with Cimbali grinders).


The radial runout exhibited by the Cimbali grinders doesn't seem to hurt performance when new. However, the runout affects particle size distribution and burr life. A little runout is prolly OK, but my first Cimbali grinder had enough runout that the grinder "walked" across the counter when motor shaft speed reached resonant frequency as it was spooling down. I deemed that unacceptable and returned it for another one.

the radial runout thing is my only bitch with Cimbali grinders. I've never seen a Mazzer grinder with such runout, and such runout speaks of sloppiness on the part of the machinist making the parts (having worked as a machinist in the past, i'm pretty familiar with how the carrier gets made). This type of runout would be a real pain in the yass if the grinder were a pure conical, but is less problematic for a flat-burr grinder.

-Greg

gscace wrote:Actually this isn't a good test. The runout I've observed is runout in which the burr doesn't rotate on its centerline, but rather rotates off-center.

Hi Greg-

Although I'm not the OP here, I appreciate your thoughts. I don't have the ability to verify my Junior observations as the grinder I referred to lives in TN with my brother.

What we observed appeared to be "wobble" or more accurately nutation of the burrs. Hence our simple "high spot" test. If mal-alignment of the center axis of the burrs is in reality the problem as you state, then I would concur with Ken that what my brother and I observed with his Junior was quite likely indeed an optical illusion.

Is it your opinion that one should "test drive" Cimbali grinders before purchase? Perhaps the alignment issue is only a rare problem? You have me curious now because I've been toying with the idea of purchasing a Junior to see how it compares to my Mini E-

Best-

Bob and I have traded a couple of emails about this prior to the posting. I have to say I have been very happy with my Jr. I do not have any machine shimmy as the burrs spin and I have been perfectly happy with the grind quality. I actually like it better than my Mini, it more 'commercial' than the Mini. However, the discussion has gotten me wondering about my machine. I will have to take the covers off this weekend and give it a look.