DaveB wrote:Question for those who have experience with Monolith - using the new locking mechanism and the previous version:
For the previous version, once you loosen the adjustment knob, how much force is required to turn the funnel?
For the new version, is there a difference in force required to turn the funnel?

And now for the $2000 question: Is there any chance of adjustment drift with the new system? The Niche has already had a couple reports of drift on HB, despite presumably being tested extensively before mass release. It seems the definitive cause has yet to be determined, although stray grease / mating surfaces too smooth may be the culprit. Can we rest assured that the new Monolith system is immune to drift under any circumstance in normal use?

Either one turns effortlessly, locking version or new lockless. Only time the locking type was stiff was when it had been turned coarse to season the burrs with pounds of coffee and then the threads were not cleared of grinds to turn back to espresso range.

The new model Does Not Drift. Period.

It's a Monolith, it won't drift. If there was a chance it would drift, Dennis would not have considered this design an improvement! I have a Flat from the first batch which you'll be amused or dismayed to find out that I watched the quantity available decrease over a few weeks waiting to see if it would actually sell. Finally jumped in when it got down to 5.

The thing about the grinder is, it is somewhere in the range of the most reliable thing I own. Not as reliable as say my Snap-On box wrenches, but seemingly not that far off. Somewhere there is a picture of Dennis' garage which clearly shows his commitment to making a perfect grinder.

And lastly, the trapezoidal pins do not have anything to do with horizontal alignment as someone seemed to indicate earlier. That shape is commonly used to allow for slight amounts of tolerance in one dimension.

Ira

ds wrote:OK, I am going to post this once and then I am bowing out of thread since its really counterproductive. Flaw with your theory and explanation is that there is no rotational force acting on the adjustment funnel to cause it turn thus it does not rely on large amounts of friction to keep it in place...

ds -- please hang in there because we are gentlemen and I find this discussion lively and intellectual. Your point about the new design which decouples the upper burr from the adjustment funnel is an excellent point and a highlight feature of the new design. I agree that this is innovative and different than other grinder designs. I do however disagree that there is

ds wrote:... no rotational force on the adjustment funnel to cause it to turn ...

, however I do agree with you that the new design

ds wrote:does not rely on large amounts of friction it keep it in place

I am not creating a theory, but carefully applying Newton's three laws of physics, which in this case is actually a little tricky. TL;DR: There exist rotational force on the adjustment funnel during operation. This force is less than the prior design, but still sufficient to require compression of the threads to prevent it from drifting with respect to the top plate. The rotational forces arises from two primary sources: 1) variation in rotational speed of the bottom burr, and 2) variation in rotational force exerted by the beans on the upper burr.

Any two bodies that touch one another experience static and/or dynamic force. In the case of the new Monolith grinder, there are static gravitational and spring induced forces between the funnel and other parts of the grinder. The entire system is mechanically coupled. A subtle part of this system is that when the bottom burr changes speed, this results in a rotational force that is imparted to the entire grinder. In other words, it causes the grinder to vibrate rotationally. The bottom burr changes speed when the motor is turned on/off, but also if one were to measure the rotational speed during grinding on a sufficiently small time scale, one would notice that the bottom burr and the electric motor are speeding up and slowing down while grinding. This change in speed results in a change in angular momentum. Change in angular momentum of the bottom burr results in rotational force imparted to the body of the grinder -- in other words rotational vibration. If you touch a grinder in operation, you can feel the vibration. It is a violent process and even a heavy grinder vibrates a little, and that force acts on everything that is connected to the grinder.

If there was insufficient frictional force between the funnel and the grinder, its position would change with respect to the top plate. If there was zero friction between the funnel and the grinder, then the funnel would stay at rest while the body of the grinder vibrated. This is Newton's first law of physics -- a body at rest tends to stay at rest unless a force is acted upon it. But the funnel is coupled to the grinder, so it does indeed experience rotational force as the grinder rotates; to prevent the funnel adjustment from drifting, it must be overcome by sufficient force between the male and female threads of the adjustment plate. This is achieved by an upward force that compresses the male threads against the female threads. While I have not seen the new design first-hand, I believe that the pictures and the laws of physics reveal the underlying static and dynamic forces at work which prevent the adjustment funnel from changing position during operation.

My apologies ds - I was rather sleep deprived and irritable when I wrote my last reply. I felt you were suggesting that def was in some way slow for not being able to follow your train of thought, which I felt was unfair hence my rather visceral and ungentlemanly response. Please excuse me.
On the plus side, I feel like I'm learning a lot about the monolith with these discussions

Without going into the gory mechanical forces involved with each component, I think we should be able to all agree that the one thing that is keeping the distance constant between the two flat burrs is the funnel mechanism. Fundamentally, this is what is used to adjust the burr seperation distance. Regardless of how much friction is required, as long as the funnel doesn't rotate, the distance between the burrs should remain constant - assuming the rest of the grinder is assembled correctly and the burr carriers are not doing silly stuff.

With regards to what keeps a screw in place, it indeed boils down to the amount of friction between the threads. No matter how much force is exerted on a screw, whether it be rotational or longitudinal, as long as there is sufficient friction to hold the screw in place, the screw will not come loose. The amount of friction needed to keep a screw in place is a function of the thread pitch (number of rotations over a given length), screw diameter, thread depth, thread count, and the coefficient of friction of the thread surface.

A big part of what cause this thread to light up in activity was that there was concerns about this new mechanism slipping during use. This concern was, in part, fueled by observed slipping of the burr settings on the Niche Zero. However, I think what has been lost in the details was that owners of the Niche Zero that reported this slipping problem also reported that they noticed excess silicone grease that worked its way into the threads. If such probem happens, the silicone grease will naturally reduce the coefficient of friction on the thread surface. As such, if there is not enough of a safety factor to account for such occurrence where the thread pitch, screw diameter, etc... could stilll provide enough friction to keep the funnel in place, then the mechanism will naturally slip.

With regards to the monolith design however, the design of the funnel is such that there is no grease required and no seepage of lubricant would enter the funnel screw as no components in the vacinity of the funnel requires lubricant. So unless someone unthreads the funnel and contaminates it with greasy fingers, the likelihood of having any form of lubricant seeping into the threads is pretty much nil. And, as a matter of serviceability, if the threads does indeed get contaminated for whatever reason, you can simply unscrew the funnel and wipe it clean with some isopropyl alcohol.

Think I get the new system mostly. There is quite a bit more parts and precision to the revised Monolith; floating burr carrier, trapezoidal alignment pins, matching burr carrier plate inset relief, etc.

Now that the upper burr carrier does not rotate, is it superior to the first generation Monolith?

hankua wrote:Think I get the new system mostly. There is quite a bit more parts and precision to the revised Monolith; floating burr carrier, trapezoidal alignment pins, matching burr carrier plate inset relief, etc.

Now that the upper burr carrier does not rotate, is it superior to the first generation Monolith?

According to JayBeck and mivanitsky:

JayBeck wrote:Since Mike wrote that a little bit has changed. Denis has carried over the redesigned burr chamber from the Max to the regular Flat. What this means is even more precision and better alignment than before. I've had private chats with Mike about it and he believes that an SSP Flat with the new burr carrier is now very, very close to the Max on light roasts, equal in medium and dark. In other words, the PRIMARY thing you gain for that extra $500 in the Max is grinding speed. You also end up with a much larger (and louder) grinder so depending on your set up that may or may not be a big deal.

I wouldn't worry about it too much to be honest.

People. This is really simple.

The burr carrier pegs are sufficiently constrained to allow, within designed tolerances, only vertical travel of the upper burr carrier.

There is no transmission of any rotational force to the funnel/screw mechanism. It is impossible.

I do not disagree with the notion that a screw thread, exposed to vibration, can drift randomly, and that in the presence of an upwardly displacing force, this drift will skew toward loosening. This may explain the rare adjustment drift in the Niche Zero

That said, and this is probably the point that some people are missing in this thread, There is not sufficient vibration transmitted to the screw/funnel to induce this type of drift.

This is due to the design/construction tolerances of the Monoliths. Until you see and feel one in action, you may not believe this, but it is true.

Spring strength within sensible ranges make no difference, as even with weak springs, burrs will find the appropriate distance when spinning with coffee. That said, the springs chosen are selected to prevent this from being necessary. Stronger springs just make the funnel harder to turn.

I have used more Monoliths with the new locking mechanism than anyone but Denis. I have never had any drift, and I make grind adjustments of 0.05 on MAX commonly.

Denis is aware of this thread. It is not appropriate for him to participate in this subforum, due to HB rules.

I would like to commend the sensible and articulate comments of ds and a few others, who clearly grok the new locking mechanism.

While just a regular participant on HB, my understanding is that that the HB rules do allow sponsors and vendors to participate in conversations to clarify misunderstandings and misinformation about the products when necessary, so if there is outright misinformation I suspect he could come in to clear up the issue, though I suppose it may not be necessary.

Personally, I have seen HB members convert to the Monolith and drop their other grinders. Many of those are the same members I have read hundreds of pages from and that are very knowledgeable and experienced, so I am sure most others are in the same boat as me and are completely sold on the quality and performance of the grinders.

I read this thread not as a suggestion that it doesn't work, but rather that those reading (like myself), or those participating, assume that Denis has designed something that works, might still have a slight bit of anxiousness as one might with anything changed/new, and are mostly just geeking out over what exactly it is and how it works, rather than questioning the performance of it.

The long wait times make it more dramatic too of course, I can't help but click immediately on any thread that has "Monolith" in the title now!