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Grinder black hole??
Lawrence
Top  #1 Print Post
Posted on 11/09/2022 8:07 PM
Newbie here asking dumb questions... has anyone heard of any intrepid legends home-brewing their own very decent grinder?

Lots of creative people ?? who can turn almost anything (haven't seen any cast iron kitchen sink or bathtub roasters here yet) into an awesome bean burner -- seem to be rolling over, opening their wallets and shelling out ("no amount of $$$ spent is enough").

Aren't powerful motors a thing, burr sets and rigid containers a thing, micrometric axis adjustment (e.g. microscope fine/coarse controls) a thing... what am I missing???
Edited by Lawrence on 11/21/2022 12:51 AM
 
btreichel
Top  #2 Print Post
Posted on 11/09/2022 11:08 PM
Interesting question.
 
renatoa
Top  #3 Print Post
Posted on 11/10/2022 2:52 AM
You don't need micrometric precision for a grinder, any decent lathe or CNC can do it.

I have two examples in my country, the well known Kinu, was been started in a small workshop with expertise in dental equipment.
The very first four alpha units were sent to some dozens of members in the coffee local forum, for expertise, probably was the first open source developed grinder ever Grin
Another grinder made in my town, less known than Kinu, is Honne, a Versalab clone, that is manufactured on demand in a facility that is not bigger and much better furnished than an auto service.
And a last example MadebyKnock, the manufacturer of Feldgrind series grinders, a single man business in Scotland, doing about 50 units per month in his home.

The burrs are another story, though... everybody buy them ready made, mostly from ItalMill. The grinder itself is nothing else than an enclosure for the burrs.
 
CK
Top  #4 Print Post
Posted on 11/11/2022 3:29 PM
Good question. There's work in progress on my Urbanic 070s to use its parts for a custom version... having RPM control, less static build-up, and hopefully near-zero retention. I'm trying to find out if my palate can taste the difference between conical vs. flat burrs in a simple home environment.
 
HarryDog
Top  #5 Print Post
Posted on 11/11/2022 4:31 PM
This guy, spins vinyl by night and grinds coffee by day.

Edited by renatoa on 11/12/2022 1:37 AM
 
renatoa
Top  #6 Print Post
Posted on 11/12/2022 10:18 AM

Quote

CK wrote:

Good question. There's work in progress on my Urbanic 070s to use its parts for a custom version... having RPM control, less static build-up, and hopefully near-zero retention. I'm trying to find out if my palate can taste the difference between conical vs. flat burrs in a simple home environment.


I have a chinese grinder in same or similar body, but using the completely out of this world ghost burrs/teeth...
It is totally other game with this style of grinding, without a single sharp cutting edge, but only pyramidal teeth, that mill like corn floor or sugar crystals, instead random chips as delivered by a grinder from the flat/conical universe.

Why would this vertical flat burrs placement would have any retention ?
Opened mine and I can't figure any place where a single bean might get lost...
10.0 grams in, 10.0 grams out !
Static yes, a bit, some powder fine as cocoa is retained around the exit spout, need a brush weekly.
 
allenb
Top  #7 Print Post
Posted on 11/12/2022 12:06 PM

Quote

renatoa wrote:

Quote

CK wrote:

Good question. There's work in progress on my Urbanic 070s to use its parts for a custom version... having RPM control, less static build-up, and hopefully near-zero retention. I'm trying to find out if my palate can taste the difference between conical vs. flat burrs in a simple home environment.


I have a chinese grinder in same or similar body, but using the completely out of this world ghost burrs/teeth...
It is totally other game with this style of grinding, without a single sharp cutting edge, but only pyramidal teeth, that mill like corn floor or sugar crystals, instead random chips as delivered by a grinder from the flat/conical universe.

Why would this vertical flat burrs placement would have any retention ?
Opened mine and I can't figure any place where a single bean might get lost...
10.0 grams in, 10.0 grams out !
Static yes, a bit, some powder fine as cocoa is retained around the exit spout, need a brush weekly.


Interesting you mention the pyramid cutting edge burr on your grinder. If it's the same as I'm thinking of, it's also used on the Fuji Royal grinder and was from a design by the Grindmaster company who came up with the particular geometry back in the 1940s here in the US. It's hands down, the best cutter for producing the least amount of fines. As we know, for brewed coffee, fines are the enemy of a clean extraction and produces off-notes.

https://www.home-...16511.html

also, look at post #20 in this thread for the grindmaster burr

https://homeroast...ad_id=2045
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
HarryDog
Top  #8 Print Post
Posted on 11/12/2022 12:36 PM
I wanted to get a grinder with ghost teeth if cheap but in Canada the price was very high at the time. I thought they generated more fines as they were sold with those sifters to combat this issue. Most youtube personalities don't really rate the cups all that high? I don't exactly trust much of what they say but it's often all you can find for information. I think it was Lance who replied to me you can't change burrs on them as you don't have enough length on the shaft? Lance.H was replacing burrs on other cheap grinders though.
 
renatoa
Top  #9 Print Post
Posted on 11/12/2022 3:23 PM
They say what are paid to say... or, "review"... how to say something about a product that nobody push, nor import/distribute. Grin

The sifting result is in the 5% ballpark, about 0.8 grams fines for 16 grams dose, while the average quota of the best grinders, for under 400 microns fraction, is 12-15%. So 2-3 times less...
400 microns is the size of the embedded sifter perforations.

Maybe people is simply not ready for a drink lacking the body all are accustomed for decades... is more about tea than coffee, if you look at the videos at the end of my rant smile

But the truth is that the actual grinders burrs is a compromise... for millenniums, the milling was a two steps distinct operation: breaking, then sifting in multiple passes, to obtain at least 3 products from the grains: bran, semolina, whole wheat and fine wheat.
Trying to do both operations successfully in a single step and device, using only the opening slot of the output circle for grounds calibration, instead a sifting, this IS a compromise...

A sign of the times, that the market turns into a different grinding approach is the really new, not released yet, but ready to enter in tests of some serious testers, not the "usual suspect" influencers that plague the coffee market, is the new Timemore Sculptor, fitted with some hybrid burrs, a mix of ghost and flat burrs.





Burrs can be seen in this second video, at minute 5, and a compare against Commandante and Fellow Ode, that are both KO after this match Grin

The most technical and intimate video is below:



end of rant smile
 
HarryDog
Top  #10 Print Post
Posted on 11/12/2022 5:18 PM
Looks to be available on Ali express but $1300 CAD (50% off) and I probably have to pay import fees and tax on top? Found one cheaper but they look to be 220v only. One site shows US plug but voltage still 220v?

I would want to taste the coffee first as I was terribly disappointed with the DF64 stock declumper and Italmill burrs. I replaced the declumper with my design and it works well. Have not found a way to fix the static and replacing the burrs with SSP HU so far was the only way to actually enjoy a cup.

I have tried two burr grinds, conical then the SSP HU burrs to finish for espresso and the texture/body really changes, much more silky and gelatin like. So this might make some difference and I think 120v grinders do benefit from adjustable RPM a bit more then some 220v grinders, depending on overall rpm. It's been awhile since I read that paper on grind distribution.

If I lived some place where I could sample these products and make a decision before buying that would be different for sure.
Edited by HarryDog on 11/13/2022 9:10 AM
 
Lawrence
Top  #11 Print Post
Posted on 11/12/2022 10:31 PM

Quote

HarryDog wrote:

This guy, spins vinyl by night and grinds coffee by day.



I preferred 45 rpm grind to 33 1/3rd. : )
 
CK
Top  #12 Print Post
Posted on 11/12/2022 10:42 PM

Quote

renatoa wrote:

Quote

CK wrote:

Good question. There's work in progress on my Urbanic 070s to use its parts for a custom version... having RPM control, less static build-up, and hopefully near-zero retention. I'm trying to find out if my palate can taste the difference between conical vs. flat burrs in a simple home environment.


I have a chinese grinder in same or similar body, but using the completely out of this world ghost burrs/teeth...
It is totally other game with this style of grinding, without a single sharp cutting edge, but only pyramidal teeth, that mill like corn floor or sugar crystals, instead random chips as delivered by a grinder from the flat/conical universe.

Why would this vertical flat burrs placement would have any retention ?
Opened mine and I can't figure any place where a single bean might get lost...
10.0 grams in, 10.0 grams out !
Static yes, a bit, some powder fine as cocoa is retained around the exit spout, need a brush weekly.


On this page we can see another user's images of retention with his grinder. https://www.home-...78203.html
My homemade bellows cleans most of the grinds out, but the large puffs of air creates another issue... blowing grinds out of the collection cup! Back to the drawing board for redesign...
 
renatoa
Top  #13 Print Post
Posted on 11/13/2022 9:56 AM

Quote

Lawrence wrote:

Quote

HarryDog wrote:

This guy, spins vinyl by night and grinds coffee by day.

...


I preferred 45 rpm grind to 33 1/3rd. : )


And better feeding... beans aren't so convinced to proceed
 
HarryDog
Top  #14 Print Post
Posted on 11/13/2022 11:40 AM
Yes, I think it's more of an art piece then a functional grinder in it's current design.
 
addertooth
Top  #15 Print Post
Posted on 11/20/2022 9:11 AM
The bulk of these comments, and the uncertainty of outcomes... is what has left me tepid about upgrading to a "big-boy" grinder. One of the best videos I saw on grinders utilized a box with progressively finer holes which graded the size of the ground coffee. Even so, it showed that even good grinders can have a significant amout of variation in the size (and shape) of the grinds they produced.

It does make me wonder if the next evolutionary step for a grinder might be a roller-mill style, as versus something which uses burrs.
 
allenb
Top  #16 Print Post
Posted on 11/20/2022 2:01 PM
If a roller mill type grinder is perfectly set up for one specific grind size, they can produce a very uniform particle size with low % of fines. OTOH, if not set up perfectly, they have a tendency to produce even more fines than typical flat burrs. We used a very expensive roller mill grinder made by MPE for production runs and I seem to remember it churning out a lot of fines relative to Mahlkonigs. The Mahlkonigs were not that great either compared to the ghost burr Grindmaster units.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
CK
Top  #17 Print Post
Posted on 11/29/2022 12:57 PM
An update on a customized grinder... Here is a rendering of my Urbanic flat burr grinder with an orientation at 45 degrees off horizontal. There is no more grind retention in the auger area of the bean path to the burrs. The addition of the bellows has made it an almost zero-retention grinder. The RPM is lowered by about 30-35% and is extremely quiet. I used this device https://www.amazo...&psc=1 for RPM control. The grinds come out noticeably fluffier and fill the basket more with the same dose. The anti-static mod means there is basically no more static affecting this machine. Finally, the flavor... this grinder now produces a noticeably smoother, less acidic, and better-tasting espresso than the stock grinder on the Barista Express. Pretty happy with this rebuild and mod.Grin
CK attached the following image:
hr_grinder_concept.jpg
 
allenb
Top  #18 Print Post
Posted on 12/01/2022 4:26 PM
Wow, that is one nice grinder! It sounds like you took all of the typical faults of grinders and addressed each one in this build. I'm pretty sure no one has ever done this to that degree. Nice work!
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
CK
Top  #19 Print Post
Posted on 12/01/2022 6:01 PM
Thanks Allen, when I get it officially painted/stained and a few other features added, I'll post a video.
 
CK
Top  #20 Print Post
Posted on 12/21/2022 2:06 PM

Quote

CK wrote:

I used this device https://www.amazo...&psc=1 for RPM control.


After weeks of use with the first control board, it failed... the fuse was still good, it wouldn't turn on anymore, the PCB LED wouldn't light, the resistor was getting very hot, and a burned smell came from the unit. It worked for many many espressos so I thought this unit became defective. I ordered another one, and after just 2 uses it failed as well. Same issues. This circuit board is not recommended for a mod to a grinder like this anymore. As many reviews have commented, it seems there is something flawed in its design... back to the drawing board.
 
allenb
Top  #21 Print Post
Posted on 12/21/2022 4:25 PM
Sorry to hear the controller was a bust! Full load current not going over maximum rating of controller?
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
CK
Top  #22 Print Post
Posted on 12/21/2022 5:05 PM

Quote

allenb wrote:

Sorry to hear the controller was a bust! Full load current not going over maximum rating of controller?


Shouldn't have been a problem... it is a 250-watt motor on a 120v circuit. The board is supposed to be rated up to 5 amps and is fused... the incoming AC supply has an inline resetable 2 amp fuse/breaker that never tripped either time. Also, on start-up, the potentiometer setting has always been at about 70%.
Edited by CK on 12/25/2022 4:56 AM
 
renatoa
Top  #23 Print Post
Posted on 12/22/2022 8:42 AM
For my grinders (Arco and Xeoleo Ghost burrs) I never start the motor loaded with beans.
Same power ballpark 150W Xeoleo, 200W Arco. On 230V.
For Arco the power was measured and never exceed 165W, with the lightest beans.
Much easy to start when empty, and lot of torque when loading beans with motor spinning.
 
CK
Top  #24 Print Post
Posted on 12/22/2022 9:27 AM

Quote

renatoa wrote:

For my grinders (Arco and Xeoleo Ghost burrs) I never start the motor loaded with beans.


We do the same... I only add beans to the flat burr grinder when already spinning. If this chart is right, it shows that a 1/3 horsepower (250w) DC motor shouldn't pull more than 4.1 full load amps. The board was failing even when starting the motor with no beans supplied.
 
renatoa
Top  #25 Print Post
Posted on 12/22/2022 9:35 AM
At start is the biggest current... if graph proportions are real, 4-5 times bigger than regular load... Shock

www.researchgate.net/profile/Ninik-Lestari/publication/352526569/figure/fig1/AS:1036227146969090@1624067212767/The-motor-starting-current-curve-Figure-2-Time-current-characteristics-at-the.png

Source: https://www.resea..._352526569
 
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