another_jim wrote:I don't want to give anything away until I've racked up about 20 to 30 comparative shots over the next week, but I'd like you to also try some milk drink comparisons if you normally make these.

OK, will do.

Abe Carmeli wrote:DAY 4

Today I was trying to determine the optimal Barista technique for the Versalab M3 grinder. Let's see some pictures:



Uneven distribution half way into the grind

The distribution out of the grinder is not always perfect as we see in the image above. (I am nitpicking here, of course). The photo was taken half way into the grind of a 14 grams basket. This does not happen on every grind but on about 50% of them. I found that a good way to fix it is simply to turn the basket or P/F 180 degrees halfway into the grinding session.

Gee, this uneveness hasn't been a problem for me. Hope this isn't a dumb question, but are you sure that you're not simply holding the pf at an angle underneath the exit funnel?

I found that tapping the p/f straight down against the counter, halfway or 3/4 way into the grinding session allows me to control the final dosage amount and still keep even distribution

I cut a piece of 1/4" thick polyethylene about 4" x 5". It lays on the base under the exit funnel. 3/4 of the way through the grind I tap the pf on the plastic to settle the grounds, which sounds exactly like what you're doing.

AndyS wrote:Gee, this uneveness hasn't been a problem for me. Hope this isn't a dumb question, but are you sure that you're not simply holding the pf at an angle underneath the exit funnel?

No angle. I hold it flat against the funnel exit gasket.

Abe Carmeli wrote:

AndyS wrote:Gee, this uneveness hasn't been a problem for me. Hope this isn't a dumb question, but are you sure that you're not simply holding the pf at an angle underneath the exit funnel?

No angle. I hold it flat against the funnel exit gasket.

Have you levelled the grinder? Since I found out my Mini sounds smoother when it's level, I've been using shims to make sure the grinders aren't atilt. Maybe a tilt can affect the the M3's distribution.

another_jim wrote:Have you levelled the grinder? Since I found out my Mini sounds smoother when it's level, I've been using shims to make sure the grinders aren't atilt. Maybe a tilt can affect the the M3's distribution.

As a matter of fact no. I'll dig out my level and check it out.

DAY 5

As of this morning, my M3 died a sudden death. There will be a reception held in my kitchen tomorrow from 4:00 to 6:00 p.m. Coffee will not be served. All well wishers may post their condolences on this thread.

It looks like power supply, but I could be wrong. The good thing about it, I will have the opportunity to checkout Versalab's quality of service. But why so soon, and why me ?

Abe,
I do Post_Mortems for Free!


Just send the unused portion (postage paid) to me...





Bummer
could just be teething pains



Sean

Sorry to hear it, hope you can get it resolved quickly.

DAY 5 1/2

The Resurrection

The rumors of my grinder's demise have been greatly exaggerated. The cause of the problem: A combination of stone caught between burrs, and a slow blow fuse on the grinder. The Versalab Grinder has a 2amp slow blow fuse that is designed to blow when a stone is caught in between the burrs. I was running my kitchen circuit at maximum load, and my kitchen fuse blew before the grinder fuse could kick in. I need to replace the 2 amp slow blow fuse in the grinder with a 2 amp fast blow.

As to Versalab service, they called me after getting my email, I spoke to John Bicht directly, and through a quick process of deduction he figured it out. They offered to have the grinder shipped back to them for repair at no cost if needed. I spoke to John about the dial scale issue and the dial retention problem, and I will post a separate note about it tomorrow.

Since I had to disassemble the burr set again, I took some more pictures for you burr freaks out there.


Lower Burr Set


Complete Burr Assembly - Side View


Last image captured by many coffee beans on their way down to the belly of the beast

Glad you're running again. A fast blow fuse on a motor may not work, since they can blow on the startup surge (I went through a box of them for my fan variac on the roaster in about a month before the doh moment finally hit).

Thanks for the burr pics. I was under the impression that the flat burrs were the same as for the DRM/Cimbali flat burr grinders. After reading the Illy and Vianni chapter, I wrote and asked Ken. The standard flat burrs, http://coffeegeek.com/forums/espresso/machines/164319 have the same dual crush and shear pattern as the mini burrs. This flat burr, with it's uniform burr spacing must be custom made for the conical/flat combos.

If you look closely, you can see that this means the actual fine grinding surface is vastly increased.

the flats from the DRM/Cimbali combo burr sets are, in fact, a different part number from the standard flat set.

gotta love a de-stoner...

lennoncs wrote:Hi all,
I was talking a bit to Abe today about the issue he was having with creep in the adjusting barrel after tightening the lock screw. I grew up in the family business of machine tools and precision tooling, so my take on statements of “precision grind adjustment” made by manufacturers may seem a bit harsh to some. I would only start to consider precision adjustments to be those that are able to be reproduced within a few tenths (.ooo1) time after time. I defer to the experts on grain size for optimum extraction to give an exact size of the grains that we want (any time now Jim )

Hi Sean,

I don't know what the exact grain size is, but what I can tell you is that in my experience there are coffees for which a 3 micron change in burr separation will result in a five second difference in shot time, i.e. the difference between a ristretto and a normal double. That's in line with your 0.0001" statement.

Best,
David

Lucky 13! On the 13th shot comparison, I finally got a godshot from both grinders at the same time from a yemen, brazil, sulawesi blend.

This, of course, means a lot more for me than comparing a statistical sample of shots, since it gives me a feel for the best the M3 can do.

I got lucky, I usually go 7 to 8 shots before getting what I consider a perfect extraction; so doing paired comparisons, I was expecting to go for 30 or so shots before being "due" for a pair of godshots. It basically makes my mind up about the grinder. I'll continue with the comparisons until I hit statistically unassailable results for the numerically minded (providing you trust my tongue and comparison grinder, a two year old mini).

Those still assessing, let me know when you want to hear the results. Those interested in the grinder, and not playing with one, email me for a write up.

another_jim wrote:Those still assessing, let me know when you want to hear the results

Jim,

It will take me another week to finish mine, but go ahead and publish your results. I can't hold my breath any longer .

I got the repolished exit funnel (edit: John Bicht thought this may be the reason grinds were being retained in the original), and couldn't detect any difference visually or by touch. Both seem to be lathe ground pieces with horizontal toolmarks and a vertical hand filing polish. I put on the new cone, and will send back the old one. The old one rarely retains grinds - a little weathering or grinder dust seems to have helped, the new one so far none (there's still a 1/2 gram from the lower burr that comes out if one jiggles the grind adjustment and pulsed the motor).

I was curious if there was a difference, so I snapped a pic and put it through some pattern enhancers in photoshop:

Here's the raw pic with no visual differences:




Here's the enhanced version with the filing marks in dark purple, and the unmarked metal in light green:



It does appear that there was an extra filing or polishing, since the horizontal circles are much more obscured in the new funnel.

Nice shot Jim. Did you invert the image using "Negative" for the X-Ray images?

I was thinking about a more elegant solution to the lack of a grinder scale. From the pictures it looks like the top funnel is made from a relatively soft alloy like brass or bronze. Would it be possible to put your own numbers on using a punch set like this one?

http://www.northerntool.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=6970&productId=32952&R=32952

Then between the numbers you could put in some "tick marks" with a center punch. I think aligning the numbers with proper spacing would be the trick, along with getting a good single strike (you'd hate to mess it up with a double strike).

Just a thought....

Thanks!

Norm

nalesch wrote:I was thinking about a more elegant solution to the lack of a grinder scale. From the pictures it looks like the top funnel is made from a relatively soft alloy like brass or bronze. Would it be possible to put your own numbers on using a punch set like this one?

Norm,

Thanks for the idea, it could be a clean solution. Perhaps first print the scale on translucent sheet and attach it to the grinder, and then punch over it. I would want to do at least two runs on a brass ring before I assault that dial

Abe,

Thinking out loud for a minute, to avoid messing up the grinder, you could punch the numbers on a strip of brass sheet and then wrap it around the barrel as Jim did with his paper scale. You could use Jim's scale as a guide for punching and if you mess up the punching, you're only out a strip of brass. Once you get it perfect, attach it with some double stick tape or whatever. This would provide an all-metal industrial art look. You could use other metals beside brass for a contrasting look (brushed Stainless steel or Aluminum). Or how about Stainless Steel tape that you can buy a the hardware store? I think there are lots of things to try.

Thanks!

Norm