All this talk about 'burr alignment' and 'tolerances' - Page 2
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malling
- Posts: 2923
- Joined: 13 years ago
Mazzer isn't as consistent as many like to believe. Test them with a refractometer and you get surpriced how inaccurate these views are.
The days when we thought mazzer where consistent, where back in the days where we didn't meassure and weight everything, every since we started doing so, the views have changed. Mazzer are only consistent in the respect that they can deliver acceptable brews within a sertain range multiple times in a row, but you can achieve brews within a narrower range with grinders with a narrower particle distribution.
It is not without reason we keep talking about grinders with a narrower particle destribution, an aspect where Mazzer just fall short! Their design is flawed, as someone else have already mentioned.
But it is simply not worth the investment to change it, as the majority of places dosen't care about these things. We should remember that the speciality industry is only a fraction of the entire coffee scene.
For mazzer the threat dos not come from small manufactures as LW but from manufacturers that produce automatized machines, that is getting better and better!
The days when we thought mazzer where consistent, where back in the days where we didn't meassure and weight everything, every since we started doing so, the views have changed. Mazzer are only consistent in the respect that they can deliver acceptable brews within a sertain range multiple times in a row, but you can achieve brews within a narrower range with grinders with a narrower particle distribution.
It is not without reason we keep talking about grinders with a narrower particle destribution, an aspect where Mazzer just fall short! Their design is flawed, as someone else have already mentioned.
But it is simply not worth the investment to change it, as the majority of places dosen't care about these things. We should remember that the speciality industry is only a fraction of the entire coffee scene.
For mazzer the threat dos not come from small manufactures as LW but from manufacturers that produce automatized machines, that is getting better and better!
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randyh
- Posts: 268
- Joined: 8 years ago
Ditto! As thoughtful and concise as most of Sam's posts. I think where the controversy lies at this time is at what point does more precise alignment stop making a difference tastewise? Discussed on another thread Sam started called "when is good enough good enough?" Or something like that. Ie is .01mm tolerance tastier than .02mm? im fairly convinced by the monolith conical thread that the extra preciseness of the monolith over other commercial top grinders makes a difference, especially when vberch did a multiple shot comparison between robur ( previous gold standard grinder) and monolith conical and showed monolith was better in every way, ey, tds, consistency, and taste. This is why I decided to buy the Kinu m47 (small budget for now but planning for monolith conical in near future)chopinhauer wrote:What a great answer, Sam. You've really distilled it down to something I can now understand and appeciate.
But let's say monolith tolerance is .02mm and Titus is .01mm. Will that translate to better espresso for the Titus?
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dsc
- Posts: 1166
- Joined: 17 years ago
I recently went from 0.05mm runout to 0.01mm on my custom build conical and the results are like night and day. I knew that 0.05mm wasn't great to begin with, but I wasn't expecting such a big difference in the cup after correcting the alignment.
Monoliths should be able to get good alignment as their maker pays attention to this (from what I've read anyway) during assembly / manufacturing and the shafts on those grinders are really short (so it becomes more of an assembly task and perhaps factoring in the right slack in parts to make sure everything can go together nicely and straight).
Mazzer doesn't seem to care at all and it's actually hard to fix alignment on their grinders as there's no easy access to the burr screws when everything is assembled or no easy way to indicate parts in relation to another when parts are mounted where they should be.
Can't really see how the EG can be aligned using the instructions on their website as the shaft seems to be supported on both ends (ie. sitting in bearings or bushings), so moving one side around won't give you much and if you force it, it won't run true anyway.
HG's are probably the worst as they have no bottom shaft support and the forces present during grinding will easily move the burr sideways out of alignment.
T.
Monoliths should be able to get good alignment as their maker pays attention to this (from what I've read anyway) during assembly / manufacturing and the shafts on those grinders are really short (so it becomes more of an assembly task and perhaps factoring in the right slack in parts to make sure everything can go together nicely and straight).
Mazzer doesn't seem to care at all and it's actually hard to fix alignment on their grinders as there's no easy access to the burr screws when everything is assembled or no easy way to indicate parts in relation to another when parts are mounted where they should be.
Can't really see how the EG can be aligned using the instructions on their website as the shaft seems to be supported on both ends (ie. sitting in bearings or bushings), so moving one side around won't give you much and if you force it, it won't run true anyway.
HG's are probably the worst as they have no bottom shaft support and the forces present during grinding will easily move the burr sideways out of alignment.
T.
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bostonbuzz
- Posts: 1261
- Joined: 13 years ago
It's also about how you measure them. Sam was paraphrasing mazzer, for instance. They may hold a high tolerance for their burrs (although frank grinds them down anyway) and electric motor shafts, but not in the adjustment or the mounting.
For a conical setup:
• The shaft has to have a low runout as measured from an indicator on the housing (ensuring the shaft is spinning in its bearings without play and is machined round),
• The housing must have a low runout as measured from an indicator mounted on the shaft (ensuring that the shaft is mounted in the middle of the housing,
• The inner burr must be mounted perfectly concentric and parallel to the shaft (matching the 0 runout of the shaft as measured from the housing),
• The shaft/inner burr must be parallel with the outer burr as measured with an indicator mounted on the shaft and running on the outer burrs and bottom of the outer burr (nearly impossible with a conical setup, but you see Frank has released a version for flat-burred the EK43).
If these are all within .0004" (very high tolerance), then added all together, it's -/+.0015, or .003", NOT including the error from the burr itself being out of round/off center, etc. Getting the total tolerance to be very small is quite difficult, mostly because of the required adjustment mechanism and the need for the user to have the ability to change the burrs.
For a conical setup:
• The shaft has to have a low runout as measured from an indicator on the housing (ensuring the shaft is spinning in its bearings without play and is machined round),
• The housing must have a low runout as measured from an indicator mounted on the shaft (ensuring that the shaft is mounted in the middle of the housing,
• The inner burr must be mounted perfectly concentric and parallel to the shaft (matching the 0 runout of the shaft as measured from the housing),
• The shaft/inner burr must be parallel with the outer burr as measured with an indicator mounted on the shaft and running on the outer burrs and bottom of the outer burr (nearly impossible with a conical setup, but you see Frank has released a version for flat-burred the EK43).
If these are all within .0004" (very high tolerance), then added all together, it's -/+.0015, or .003", NOT including the error from the burr itself being out of round/off center, etc. Getting the total tolerance to be very small is quite difficult, mostly because of the required adjustment mechanism and the need for the user to have the ability to change the burrs.
LMWDP #353
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bostonbuzz
- Posts: 1261
- Joined: 13 years ago
If you scroll down in my Grindmaster 890 thread The Grindmaster 890 you can see an indicator setup measuring the immobile burr's concentricity and parallelism. To measure concentricity, the indicator is on the shaft, measring the outer diameter of the burr, and for parallelism the indicator is measuring the outer-most cuts in the burr (bouncing around, but giving a consistent reading on the high points). The same can be done with the moving burr if you mount the burr holder in reverse.
See this link for more some images of concentricity and parallelism (ignore the laser part) http://www.mmsonline.com/articles/helpf ... hine-shops
See this link for more some images of concentricity and parallelism (ignore the laser part) http://www.mmsonline.com/articles/helpf ... hine-shops
LMWDP #353
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dsc
- Posts: 1166
- Joined: 17 years ago
2 and 3 will be concentricity problems, but it's easily doable if you leave enough slack in the mounting bolt holes for example (or design the grinder so that it allows for alignment), so that during assembly you can indicate parts and set them up right. 1 and 4 are connected as in if you have runout you won't get parallel parts in the horizontal plane ie. if the shaft wobbles on the end it will effectively wobble the burr as well (even if the burr is machined perfectly).bostonbuzz wrote: For a conical setup:
1 The shaft has to have a low runout as measured from an indicator on the housing (ensuring the shaft is spinning in its bearings without play and is machined round),
2 The housing must have a low runout as measured from an indicator mounted on the shaft (ensuring that the shaft is mounted in the middle of the housing,
3 The inner burr must be mounted perfectly concentric and parallel to the shaft (matching the 0 runout of the shaft as measured from the housing),
4 The shaft/inner burr must be parallel with the outer burr as measured with an indicator mounted on the shaft and running on the outer burrs and bottom of the outer burr (nearly impossible with a conical setup, but you see Frank has released a version for flat-burred the EK43).
HG-type design allows for conical burr checks from the bottom, but lacks the shaft support on the bottom as well. EK / Grindmaster type grinders indeed offer fairly easy alignment and make DTI testing easy.
As you said, quite often there's talk about tolerances / precision but completely irrelevant numbers are being mentioned. I've seen a quote from Mazzer which said something along the lines of "we machine burrsets with 0.001mm precision", which at the end of the day doesn't really matter if you stick those burrs on a shaft which wobbles like crazy.
I think it's a good idea to look at LPA charts for typical grinders and see what size particles make the most of a standard espresso level grind. Then compare that to the runout / error values you are seeing and think how that will affect your desirable particle size range.
T.
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CoffeeBar
- Posts: 644
- Joined: 10 years ago
( For EK43 users ) One could use these tools to get align their burrs in high accuracy? https://www.coffeeparts.com.au/machines ... nment-tool
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CoffeeBar
- Posts: 644
- Joined: 10 years ago
Video about Helor 101 tolerances http://www.ikoo8.com/video_play/XOTQ3NTEyODcy.html
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mirceat
- Posts: 27
- Joined: 8 years ago
On the same note, a video on KINU prototype coffee grinder- zero eccentricity test
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ds
- Posts: 669
- Joined: 11 years ago
Readings like this are fairly meaningless without load being applied. They do not show how concentric burrs are or whether shaft is centered at all... The only thing it shows is that shaft is machined straight, which these days is not big feat...
