Ordered the burrs and found somewhere to get a tap and stainless steel bolts when i find out what size i need.

Was thinking i could use stainless steel washers on the bolts between the stationary burr and the body of the grinder to shim it out?

How sharp were the burrs you got? they looked quite old?

i used the milk carton cardboard cut to the exact shape of the burr because then no coffee can get behind it. it you had washers there would be a space for coffee to build up behind the burr. i think i may end up using something metal to shim it eventually.

the burrs are old, from a local cafe. some rust spots still sharper than the stock burrs.

you can use the stock bolts to get a good idea of what size to buy for the new bolts. you may get lucky and find a tap that matches the stock bolts so you can use those.

lets us know how it works out.

jon

ill try it with some thin plastic sheet i have then, dont have access to any sheet metal to make a shim from.

Theres a great site in the uk, http://www.stagonset.co.uk. Sells stainless steel bolts and nuts etc with no minimum order and cheap postage and packing. Makes it easy to get just 6 good quality bolts the exact size you need cheaply.

Be interesting to see the effect brand new burrs have on it.

did it today, was really easy and the grind does look ALOT better. Just need to dial it in again now.

keeelar!

keep me posted.

jon

spoke to soon! By the third grind there was a whole portafilters worth of coffee stuck inside, including whole beans :S Had a bit of a fiddle but ended up putting the old burrs back.

Think the mod has potential, but i dont have the time or skills to perfect it.

did you look up inside where the coffee comes out to verify the burrs are touching? i couldn't figure out why it ground so bad until i looked up into the exit chute and was the burrs not touching.

it took me 3 layers of milk carton, about 3/16", to shim it out enough to get the burrs to touch. also, the material i was using initially, would crush and didn't really shim the burr out very much. something metal would be best.

this could be the problem.

jon

I have written this in the KitchenAid forums. The guys out there were sadly discussing the dull burrs and the possibility of KitchenAid offering new set of burrs, until someone came up with the idea of trying to buy a new set of Mazzer Mini burrs for the sole purpose of using them in the Pro Line:

Source URL: http://www.kitchenaidconversations.com/ ... hichpage=2.

Hello,

I do not recommend buying a new Mazzer Mini set of burrs for the sole purpose of incorporating them into the Pro Line grinder. The gentleman who did this in the home-barista forums did not notice that the stationary burr did not sit properly in the groove, but was rather laying on the edges because of the slight difference in the outside diameter of the two burr designs (the Mini burr design is millimeter-based with the OD being exactly 58mm, whereas the Pro Line burr design is most probably inch-based with the OD being approximately equal to 57.5mm). This improper seating of the Mini stationary burr in the Pro Line will cause a plenty of problems, and will simply ruin most of the Pro Line grinding chamber design calculations, leading into a very slow grinding action, a very large amounts of retention in the chamber, and will lead to operating the D-shaft in the far loose range, risking unplugging it from the motor in the coarse settings. Proper incorporation of the Mazzer Mini burrs actually requires a number of innovations, and will lead in the end (if carried out successfully) to a considerable enhancement in the grind quality/and repeatability for espresso. Nevertheless, there will still be "some" of the old bitterness; Now it isn't awful, but still there. This makes me think that it's just NOT PRACTICAL nor ECONOMICAL to go into this route, added to this is the following fact:

The crushing in the Pro Line, which is the source of bitterness, is inherent in the design, and is not only due to the dull burr edges like what is believed by most authors here. The crushing actually starts to happen PRIOR to reaching the burrs, namely between the auger and the BACK of the stationary burr. The successful utilization of the Mazzer Mini burrs in the Pro Line grinder does eliminate the bitterness that results from the grinding of the dull burrs, but NOT that of the auger crushing action. Dealing with this part requires even more innovation, and can simply lead into re-designing the whole grinder, since the knob dialing system is simply inappropriate for espresso, and since the vertical burr arrangement is inferior in terms of rigid burrs mounting to the horizontal arrangement. That is, it's not possible in the Pro Line to get the burrs very close to one another without touching. And please, don't tell me that the 3 thick springs used to stabilize the micrometric dialing system in all the Mazzers are just over-design, and simply there for the mental amusement of the Italian designers!

For those of you who are so passionate about the Pro Line because it simply beats all the nuisances of most grinders, though fails dramatically in the one thing it was built for, I strongly agree. I also believe in it, and have come to like it after I was stuck with it for a number of reasons. So, just keep it in the garage until a modification kit shows up that will turn all the the Pro Lines out there into a quiet, fast, domestic, and much more beautiful Mazzers

By the way, LibertyPatriot, a set of machined burrs is not a slight addition to the price of the Pro Line, believe me, these things are PRETTY expensive, I criticise the Pro Line for its grinding mechanism being the cheapest part, but good grinding mechanisms are expensive, and account for a considerable part of the price of good grinders. However, like I said the problem with the Pro Line is larger than the burrs, still machined burrs can help greatly, but will their cost be justified in a crushing-based grinder like the Pro Line? I think that the Pro Line designers don't think so, and maybe prefer to be able to manufacture the burrs themselves rather than to buy them from Italian sources.

I also would like to add, that in the photos above, although the KitchenAid grind looks much smoother, and although the Mazzer grind has manifestations of clumping, the Mazzer grind is much more uniform, which is apparent upon looking at the edges where a single layer of the grind is shown in front of a white background. The actual reason why the clumping is practically eliminated in the Pro Line is not due to the metal construction, since this is shared amongst most heavy-duty high-quality grinders, like the Mazzers and the Mahlkoenigs, but is due to how the Pro Line works:

In the Mazzer, most of the time whole beans enter into between the burrs, and start to get sliced from the very beginning according to the decent slicing scheme incorporated into the design of the two burrs, added to this is the fact that the mounting is superior, and the dialing is stabilized with 3 thick compression springs, allowing the two burrs to come too close to one another while still being totally parallel. This very well planned grinding in which the machined burrs are the only participants will always lead into heavy charging of the grind and will always lead into clumping. In the Pro Line however, the burrs are used only slightly to "fine tune" the crushed whole beans, which means much lesser usage of the burrs, much lesser charging, and arguably doesn't justify the cost of machined burrs.

Given that the burrs grinding action is actually the source of clumping in any good grinder, I am wondering if ceramics were chosen in the swift to overcome this, giving that the swift must not only grind, but distribute and tamp, which is a difficult task to be done by the machines if clumping was excessive (as it usually is).

Best Regards,

orwa wrote: This improper seating of the Mini stationary burr in the Pro Line will cause a plenty of problems, and will simply ruin most of the Pro Line grinding chamber design calculations, leading into a very slow grinding action, a very large amounts of retention in the chamber, and will lead to operating the D-shaft in the far loose range, risking unplugging it from the motor in the coarse settings.

Sorry - I don't buy it. In fact, I'm boggled trying to understand your assertion about "grinding chamber calculations". Maybe you could provide some specific details or facts? As far as I can tell, using burrs from a Mazzer dramatically improves the grind quality (of course I'm only judging by pictures I've seen online).

Did you try it yourself and have problems or are you just speculating?
(Was the post made while wearing pajamas? )

Assuming that the burrs set flat on a parallel planes and the moving one spins with axial alignment:
How does the grind get slowed down by a 0.5mm change in the staionary burr's OD?
How exactly is grind retention altered if one shims the burrs to get original spacing?


One more thing - Mazzer Mini replacement burrs are expensive compared to what? I checked yesterday and new burrs run about $40. To me that's a small price to pay a dramatic improvement in grind quality, but honestly I wouldn't bother unless I was intending to grind for espresso.

As far as I can tell, using burrs from a Mazzer dramatically improves the grind quality (of course I'm only judging by pictures I've seen online).

Given the fact that I am using the La Pavoni Professional, that is; probably the most demanding domestic espresso machine ever in terms of grind quality, and given that I have been using one "Modified KitchenAid Pro Line" next to it for a good deal of time now... Not mentioning that you are the one who's "judging by the pictures he's seen online"... I believe it's pretty clear who's the one who's "speculating". And by the way, I wasn't dressed up like you when I wrote that and I was indeed wearing my pajamas .

Yes, I will explain this to you, the slight difference in the outside diameter like I said won't enable the new Mazzer Mini stationary burr to sit in the groove of the Pro Line body. Probably you don't know that there is a circular groove in the grinding chamber of the Pro Line in which the stationary burr sits, which is by the way 3 whole millimeters deep. Forcing the burr to sit on the edges of that groove rather than to sink into it does make it look like around 2.75 millimeters thicker (because of the burr chamfer)... This is how the D-shaft is suddently forced to function in the far loose region, risking unplugging from the motor like I said. However, it may not be as clear why the grinding seems to be slower and the retention is so much exaggerated in the new configuration, which is briefly touched on below.

The size of the grinding chamber is increased significantly due to the improper seating of the new Mazzer Mini stationary burr, and because of the centering cavity in the bottom of the burr as well, there is suddently a plently of space for the grinded coffee to get into. The result of this is that the first whole double-shot deal of beans will get swallowed by the machine , and only after that, the grinding will continue, but will stay significantly slower than before, and the vital question is why.

The inside diamter of the Mazzer Mini burr is considerably larger than that of the original burr, that is, 33mm compared to maybe 28 millimeters. The inside diamter of the original burr is DESIGNED to crush the beans by the auger upon entering into between the two burrs, this is how the static issues in the grinder are minimized as well as how the grinding speed is so much increased regardless of the sober 400 RPM geared motor. The new inside diameter makes the crushing less frequent, and increases the probability that whole beans will make it into between the two burrs, which is exactly why the grinding speed becomes much slower, that is, this isn't how the KitchenAid Pro Line was designed to perform. The burrs in the Pro Line like I said "fine tune" the already smashed beans, which also gives some insight into their one or two-phase pattern (I am talking about the burrs). I hope that these few explanations give you an idea about what I meant by going against the grinding chamber design calculations. They are simply the naive geometerical relations that make the whole grinding thing possible.

One more thing - Mazzer Mini replacement burrs are expensive compared to what? I checked yesterday and new burrs run about $40. To me that's a small price to pay a dramatic improvement in grind quality, but honestly I wouldn't bother unless I was intending to grind for espresso.

Expensive compared to stock cast burrs that you can make in-house in large quantities, rather than needing to search for some Italian manufacturer to source them. Quality machined burrs aren't a commodity, otherwise there would've been a lot of Zassenhauses (companies that make such fine hand grinders in which the grinding mechanism is mostly everything, which people request from all over the world), and like I said, the improvement is not like what you think upon incorporating the Mazzer Mini burrs in the Pro Line. This is (again) due to the poor mounting of the burrs in the vertical arrangement which prevents having a grind that is as even as the Mini's, plus the fact that the auger crushing still happens with the Mini burrs, though less frequently.

According to my personal experience, the bitterness persists.

Best Regards,