EK43s Burr Alignment

Grinders are one of the keys to exceptional espresso. Discuss them here.
IridiumBlackberry

#1: Post by IridiumBlackberry »

Hey all,

last week I received my EK43s, which has a Revised Titus Burr carrier and SSP multipurpose burrs, and after doing a chirp test I'm not too sure about the alignment of my grinder. I figured that since it's an early 2018 model it should have the inner chamber machined to 0.01 mm, so that shouldn't be an issue and with the Titus revised carrier that should also be 0.01mm. Therefore, I then decided to do a marker test. I found that the inner chamber resulted in a fairly clean circle with no obvious misalignment, but the outer burr had one side of the burr still untouched.

Could the burrs be the issue? Or is this perhaps a tolerance stack issue? Lastly, Is it even worth chasing the perfect marker test?

Another thing I realised is that I'm not using a torque wrench to fasten the dial plate to the grinder; I'm currently just tightening them till the point, with little pressure, I can't turn anymore.

Maybe I've had too much coffee today.... :lol:

Eiern

#2: Post by Eiern »

Hi, congrats on the grinder! And welcome to the hassle of the EK43. The marker test works fine for the static burr, but for the moving burr I think you'll get a headache trying to perform it, it can work but it's no fun.

The EK just isn't that precise in it's moving burr in my experience. Just try to get the same marker results three times in a row without doing anything and you'll see that all these moving parts has enough play to allow for slight differences. A layer of marker is very thin. And remember to use the same (and measure both) mountings of the carrier on the shaft (mentioned earlier in another thread).

A better approach is lay it on it's back, remove the bag holder/spout and hopper and open the burrs enough with the dial to put a feeler gauge between the burrs. Then rotate the burrs by your finger on the auger, and measure if some areas bite down on the blade (close the burrs enough to bite the feeler blade a little) and some have more room. Measure all around the burr. You can mark the high or low spots on the side of the burrs by small markings with a marker.

I found my burr to be almost perfect with my Titus carrier. I did place one shim of 0.014mm aluminum foil, but I'm not sure if I would taste the difference in a blind test and extractions doesn't measure different.

Here's my H.U. burrs with marker method:



I will say it's important to get the moving burr perfectly centered on the carrier so that you get the minimum vibrations running the grinder. I use feeler gauges between burr and the wipers, and I double check with the auger mounted without the spacer so that I can rotate the auger and burr on top of each other and get a good view of any wobble against the static burr. Grinder makes less noise and vibrations and take a long time to stop when this is correct. Feels like it's starting faster too.

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IridiumBlackberry (original poster)

#3: Post by IridiumBlackberry (original poster) »

Yeah, I did know how much joy I'm getting into once I purchased one of these! I guess one issue is always transparency as I never know really what
the tolerances are on all these parts. I also have the feeling that the older revised carrier might not be to tight enough spec.
Eiern wrote: And remember to use the same (and measure both) mountings of the carrier on the shaft (mentioned earlier in another thread).
I'm not too sure what you mean by this. Which Mountings? The carrier is just mounted to the shaft. My carrier fits very snugly on it.

Eiern wrote:
Eiern wrote: I double-check with the auger mounted without the spacer so that I can rotate the auger and burr on top of each other and get a good view of any wobble against the static burr.
I'm also having difficulty visualising this. Do you have a video by any chance?!

Which feeler gauge width are you using for the concentric alignment?

Eiern

#4: Post by Eiern »

I use the feeler gauge thickness that gives the most snug fit, I have multiple ones as they're pretty cheap.

I mean when you put the burr carrier on the shaft there is two possible ways to have it positioned on the shaft with the shear plate mounted, one is 180 degrees off the other one.

And by removing the spacer I mean the piece on the very inner end of the shaft, near the motor, mostly inside the opening there, and when it's out I put the burr carrier on as I would when putting everything together again. This means the burrs can rub without any force applied, it's just loose.

Eiern

#5: Post by Eiern »

This is the part I take out

bettysnephew

#6: Post by bettysnephew »

Torquing the burrs will definitely give a better alignment than feel but I would be closely inspecting for a small grain of coffee or metal chip that might be on the carrier or burrs, it obviously doesn't take much to change alignment. I know Terranova and SSP do excellent work but it can't hurt to check if a chip may have been stuck in the threads and got under the burr or a small coffee ground somehow got into the assembly. From what you have said I would concentrate on the burr carrier and burr on the carrier, as a chip could have been in the threads of the screws or the carrier itself.
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IridiumBlackberry (original poster)

#7: Post by IridiumBlackberry (original poster) »

bettysnephew wrote:Torquing the burrs will definitely give a better alignment than feel, but I would be closely inspecting for a small grain of coffee or metal chip that might be on the carrier or burrs, it obviously doesn't take much to change alignment. I
Hey Betty, thanks for the idea. I'll double-check the carrier tomorrow and see if there's any coffee that could be under the burr.

I received a torque wrench today, albeit a fairly cheaper one, but I feel that it helped a bit. I uploaded a quick video showing the results of the burrs touching. I'm comparing it to the Barista Hustle video on the sound of aligned burrs.

http://www.youtube.com/watch?v=6OeVmH5F_bc

Tomorrow I'm going to reapply the marker method and see if the torque wrench helps. If it doesn't, I'll look at perhaps shimming with the feeler gauges like Eiern said.