Assessing burr wear by look or feel

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charlesaf3
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#1: Post by charlesaf3 »

I'm in the process of doing a more or less complete disassembly on the Cimbali max jr. hybrid (I should post pictures, I guess).

I've cleaned the burrs with picks, brushes etc, and dropped the upper burr assembly in espresso machine cleaner overnight, so it's pretty clean.

I'm trying to decide if it's worth replacing the burrs, which I gather are stupidly expensive. I know pretty good visual and touch tests for a number of sharp objects, which has me wondering if anyone knows one for grinder burrs.

Obviously, best proof is in the cup, but this thing is really a pain to disassemble, my urge to put it back together to see if cleaning was enough is low, if I can avoid it.

charlesaf3 (original poster)
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#2: Post by charlesaf3 (original poster) »

I think the question is still a useful one, but I think I might be able to replace just the flat burrs with the Cimbali Jr. burrs, will call chris coffee and find out

Marcelnl
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#3: Post by Marcelnl »

Is there a reason to replace them or to think that it is needed? How old, how many kilo's/pounds on them? If you don't know it makes sense but if only used at home and a couple of years old there should be no problem with sharpness imo.
LMWDP #483

charlesaf3 (original poster)
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#4: Post by charlesaf3 (original poster) »

Note, per chris (and some Research here) the Cimbali Max Jr. hybrid burrs have to be special ordered by them. However, they said they have never had to order a set, and that Cimbali claims they will last effectively forever ( I assume due to the conical pre-grind).

The burr set would appear to be the same as the Cimbali Max.

The grinders do evidently (from personal experience, boy do they.. ) tend to get quite dirty. Cleaning things will puportedly resolve the issue.

I'll try to remember to up date this for posterity after putting it together and dialing it in. Notes- the brass burr carrier is reverse threaded, with an enormous number of threads. I plan to use the food safe lubrication chris sells to put it back on, as I had to use a big pipe wrench to assist the removal at points.

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HB
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#5: Post by HB »

charlesaf3 wrote:I'm trying to decide if it's worth replacing the burrs, which I gather are stupidly expensive. I know pretty good visual and touch tests for a number of sharp objects, which has me wondering if anyone knows one for grinder burrs.
Same question was answered last week: How to tell when grinder burrs need replacing?
Dan Kehn

charlesaf3 (original poster)
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#6: Post by charlesaf3 (original poster) »

Marcelnl wrote:Is there a reason to replace them or to think that it is needed? How old, how many kilo's/pounds on them? If you don't know it makes sense but if only used at home and a couple of years old there should be no problem with sharpness imo.
what made me think I needed to replace them was that my grind adjustments were doing what normally happens with dull burrs, ie tighter and tighter and extraction issues. I'd guess I ran around 4-500 pounds through, so I was thinking I might be at the end of the range, but I guess not.

Hopefully it was just a gunk issue. I rund grindz through, but it was still impressively gunky in there

Marcelnl
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#7: Post by Marcelnl »

Would clean first and them see what comes out, 400-500 pounds does not sound like a lot imo...
LMWDP #483

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keno
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#8: Post by keno »

I had a Max Junior Hybrid a while back. It has a mixed flat and conical burr set (hence the hybrid).

I think there should never be a need to replace the conical burr as its sole function is breaking the whole beans into smaller pieces before the flat burrs do their job. Plus since the cutting surface on the Max Hybrid flat burrs is much longer than on true flat burr grinders they should last considerably longer than standard flat burrs.

Otherwise, I agree with others that the best way to determine whether to replace the flat burrs is to estimate total usage based on months and lbs per month. If you don't know them you have to go based on taste and performance. Is it difficult to dial in? Or does it just taste off?

charlesaf3 (original poster)
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#9: Post by charlesaf3 (original poster) »

HB wrote:Same question was answered last week: How to tell when grinder burrs need replacing?
yes, I'm familiar with that, I think I should have phrased it a bit differently (and had missed stefano's comment). The thing is, available data was confusing, as running my fingers over the burrs didn't result in the response I expected.

Perhaps its a lack of clarity - when we test knives etc. we use the finger nail and look at the shaving. High grind tests we use arm hair, actually (that's surgical level).

There are also some bright light reflection tests, which I can't figure out how to do. I also don't know how sharp burrs are supposed to be - I'm guessing maybe 600?

Per the discussion with the chris tech, these should be sharp. Assuming that, I'm going to attempt a calibration. Though if they are lifetime, as purported, in home use, and my big conical also is, this wouldn't be particularly useful info for me...

charlesaf3 (original poster)
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#10: Post by charlesaf3 (original poster) »

keno wrote:I had a Max Junior Hybrid a while back. It has a mixed flat and conical burr set (hence the hybrid).

I think there should never be a need to replace the conical burr as its sole function is breaking the whole beans into smaller pieces before the flat burrs do their job. I agree with others that the best way to determine whether to replace the flat burrs is to estimate total usage based on months and lbs per month. If you don't know them you have to go based on taste and performance. Is it difficult to dial in? Or does it just taste off?
Yeah, should have been more specific, was wondering about just the flats, I agree on the conical. My primary thought was taste/dialing in/channeling - it was acting like the known indicators of burr wear. Went from around 2.5 as a normal setting, to around 1, plus the assorted other issues. So my immediate thought was time for new burrs.

Frankly, if they weren't a $300 special order item I would have put them in on general principles, considering the fun involved in disassembling this machine. But given thats a decent amount to put towards another grinder I figured I'd try to analyze these burrs

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