I finally got around to replacing my super jolly burrs a few months ago, and have recently been having an intermittent (but repeatable) problem when adjusting between espresso and drip grinds.

When at an espresso grind (around the 0 mark on mine), the motor turns completely freely and has been doing a great job. If I then adjust up to drip (around the 3 mark) and run the motor without having put any coffee in the throat since the adjustment, everything is fine.

I just did a test to see just how sensitive this effect was. I freshly adjusted from espresso grind (which was working perfectly all weekend) to drip grind. Powered up with no coffee and the motor spun freely. I put ~5 grams of coffee in the throat; after the coffee was ground and I turned off the grinder power, there seems to be some friction as the burrs are spinning down. After turning off the power, the assembly clearly isn't spinning entirely freely, and only spins for maybe 1/3 as long as it normally would when coasting to a stop.

If I then try to adjust back to an espresso grind, the collar becomes impossible to turn after only about "half of a big number" adjustment. When this first happened, I assumed there was just some partially ground coffee preventing the adjustment (as had happened before), so turned on the motor to try to clear it, and got a harsh/high-pitch sound as the burrs turned (I'm tempted to say metal-on-metal, but I can't see how this would be as the adjustment is still 2.5 big numbers coarser than espresso). Immediately killing the power, the motor braked to a complete stop in just 2-3 seconds. Attempting the same adjustment with the motor on while adjusting produces a similar harsh sound.

Oddly(?), I've been reliably able to remedy this by just taking off the upper burr collar, sweeping out the throat/grind chamber, running the motor for a few seconds, and reassembling. After doing that, I can immediately adjust all the way down to espresso grind and the motor turns completely freely.

I'm totally perplexed as to what could be causing this. If my burrs weren't seated properly, I shouldn't ever be able to successfully adjust and grind for espresso. If it were just pieces of coffee, they should grind up quickly and clear the grind chamber when the motor is running -- yet disassembling reliably fixes the problem (which immediately manifests itself again after grinding any coffee at drip setting, yet I've never noticed it at espresso setting)

Any ideas?

The burrs will always bind if you try adjusting from a drip/vac pot setting back to a fine(espresso) setting with the motor off as there are still bean fragments between the burrs. If you adjust finer only when the grinder is running you shouldn't have any issues.

Hmm, I am indeed able to fully adjust from drip to espresso if I do so with the motor on. Though it still makes an intermittent 'rubbing' sound as if one side were touching something and the other not (or the lower burr were off-balance or something), and comes to a halt much more quickly than I've become accustomed to. And given your comment, John, it's odd that I never had this problem with my old burrs.

Maybe I'll try removing the burrs, cleaning things out, and re-seating later tonight. The mazzer top and bottom burrs are identical, right?

The warranty and instructions state, unless I am mistaken, that the grind setting should never be adjusted UNLESS the grinder is running. IIRC, if done on the Kony it voids the warranty according to 1st-Line.

While adjusting to a more coarse setting with the grinder off in unlikely to do damage, if you have a bean in there (such as stuck to a burr or even just some stray grounds) when adjusting towards a finer setting, the coffee will be compressed and this can damage the grinder.

jamori wrote:Maybe I'll try removing the burrs, cleaning things out, and re-seating later tonight. The mazzer top and bottom burrs are identical, right?

They are the same & it certainly wouldn't hurt to recheck your work.

1) Both burrs in the pair for SJ and Major are identical - there is no top or bottom per se

2) Must have motor running when adjusting grind more than about one or two of the tiny idents - if you are going from drip to espresso that's usually three full number settings and if there's coffee in the grinder you can't do it without the motor running.

3) Prior to setting up a dedicated drip grinder in my kitchen I did this with my SJ and Major but my strategy was to shut the slide gate when I was grinding for drip and let the remaining beans in the grinder throat all get ground or drip. Any extra drip grind coffee that would be used at that time went straight in the freezer in a ziploc for my girlfriend (she was drinking Maxwell House when she met me - pre-ground drip coffee of good origins from a freezer stash is an upgrade for her). Then I could run the motor and adjust back down to espresso setting without having a bunch of mixed grind sizes ina batch.

4) Assume that your zero point will be different when you put in new burrs. Mine always is and I have changed many burrs sets on multiple SJ's and Major's. The exact zero point - relative to the numbers on the collar - tends to be a different on different units but I always see it change a bit when new burrs are installed.

5) If you have not already done so it is useful to thoroughly degrease and clean the threads on the grind collar and the inside of the grinder body. Might even need a small scribe type instrument to scrape out some of the fine stuff on the grinder body. Once both sets of threads are truly clean then a small bit of food safe / food grade silicone spray lubricant gently wiped on the threads is an ideal way to have less resistance when you are changing grind settings (but you should still do it only when the motor is running.) You can wipe on a thin film of mineral oil but the silicone spray is a better choice.

Phaelon56 wrote:Might even need a small scribe type instrument to scrape out some of the fine stuff on the grinder body.

DON'T SCRAPE ANYTHING IN THE THREADS

Thread galling seems to be the most prevalent with fasteners made of stainless steel, aluminum, titanium, and other alloys which self-generate an oxide surface film for corrosion protection. During fastener tightening, as pressure builds between the contacting and sliding thread surfaces, protective oxides are broken, possibly wiped off, and interface metal high points shear or lock together. This cumulative clogging-shearing-locking action causes increasing adhesion. In the extreme, galling leads to seizing - the actual freezing together of the threads. If tightening is continued, the fastener can be twisted off or its threads ripped out.

The type of scribe I refer to looks a bit like a dental pick with a 90 degree angle and a very thin point on the short bent end. I've rehabbed grinders that had so much gunk and fine coffee dust solidified into the threads on the grinder body that repeated soaking with degreaser and scrubbing with various stiff bristle brushes could not remove all the debris. A very gentle pull through the suspect areas with a very fine point loosened the remaining gunk so that some additional brushing and a bit more degreaser woudl finally get them completely clean.

Perhaps I've just been remarkably lucky or maybe it's because I do this only where absolutely necessary and use gentle pressure... but of the 15 or more grinders I have cleaned this way I've never damaged a thread and all have resulted in being able to screw the adjustment collar on easily and make further grind adjustments with minimal effort.

I understand and respect your concerns about it but it's a process that was passed along to me by others who were cleaning and rehabbing grinders long before I was and properly done it does not appear to present undue risk. On the other hand... if you can suggest a process and material that eliminates the need to do this when severely encrusted threads are found - I am open to change.

Phaelon56 wrote:The type of scribe I refer to looks a bit like a dental pick with a 90 degree angle and a very thin point on the short bent end.

DO NOT DO THAT TO ANY GRINDER! EVER. I agree with cafeIKE.

Compared to many other grinders, the threads of the Mazzers are precise, and they take more stress than most other grinders because of the spring loaded design. Worst case, use a microfiber rag (in need be, dampened with espresso machine cleaner or similar) and wipe them clean. A toothbrush would also be OK, but never use any metal tool on those threads. After cleaning apply a bit of suitable lubricant to the threads before reinstalling.

I'd sic my dogs on anyone approaching my Kony with a metal tool in hand.

Hi guys,

I doubt Owen was suggesting jamming the metal tool into the threads as hard as you can, simply run the fine thin tip of the tool along the threads, without applying any pressure and it will work without damaging anything. Stuff usually simply falls out of the threads when you do that and the grinder works fine afterwards.

I understand panic mode if an angle grinder was suggested for cleaning out the threads, but not a small tool like a dental pick.

Regards,
dsc.

My Pallo tool worked great on the SJ burrs. They are plastic so I was never really concerned about damaging anything, but they were stiff enough to get off the compacted coffee when someone adjusted finer without the motor on.

I've also had this problem when trying to grind for turkish straight out of the machine. It worked for a while, then bound up and had to clean the burrs. I probably shouldn't have tried, but oh well, learning experience.

Could be a silly thing, but...

Sometimes, bit of coffee are stuck on the burrs. Not a big amount, but enough. When turning off(if single dosing), with the burrs spinning down, it can almost sounds like the burrs are touching, and unevenly at that. First time I heard it, I was scared to death. Then i read that coffee on the burrs can cause a chirping sound. I confirmed this, by having the sound go away by either 1)pulsing the grinder on/off 2)grinding through more beans.

It doesnt sound exactly like burrs touching, but it's close. If you've never heard it before, it can be scary, and sound like something has gone bad.

reason I bring this up, is because the few times I ground for french press using the Major, I heard this sound when zeroing the burrs again, and was tricked into thinking I was at the zero point, but was really in the espresso range, on the coarser side.

Still, Id open her up, clean things out, and have a look-see. Cant hurt the clean.