JT64/ LR Lufeibao 64mm Grinder - Page 12

Grinders are one of the keys to exceptional espresso. Discuss them here.
Pflunz
Posts: 139
Joined: 4 years ago

#111: Post by Pflunz »

I checked and measured my V2 JT64 grinder. I found some issues, which I am going to solve in the next few weeks.
  • The standard burrs do not fit on the top (fixed) carrier holder. Instead on the boarder of burr, the contact is made where the screw holes are. My SSP burrs do not seem to have this problem.
  • The bottom carrier is the true weak point of the grinder. The hole in mine is not centered (off by 0.1mm) so that even when the motor shaft is nicely centered (which it is) the burr is wobbling around. Additionally, the fit from the carrier for the shaft is too loose. This is the main reason for the radial wobbling. The axial stablity is also not well, as the carrier is axially only fixed by pressing it on the inner ring of the bearing. Due to the small diamter of this ring (20mm ring with 14mm inner hole) there is lots of room for errors.
The first error can be fixed quite easily by the turning machine.
For the second one, I think i will increase the shaft hole and insert an additional bearing ( SS 6807 2RS ) between the carrier and the bottom part of the grinding chamber. This should keep the carrier radially and axially centered. Due do the large size of the bearing ( 35x47x7 mm ) this should be way better than with the small bearing in the middle.

BentSimon
Posts: 3
Joined: 1 year ago

#112: Post by BentSimon »

Hi Pflunz

Can you Tell or show Picture Howe u mensurer the off cent :? er - i Try and end up with it spot on, but maybe Im doing it wrong ?

Pflunz
Posts: 139
Joined: 4 years ago

#113: Post by Pflunz »

Hi, as I wrote the burr carrier was way off on my version 2, so I went down to my basement:

The rotary burr carrier was the largest problem. The center hole was too large, which caused a wobbling (you could see this clearly by looking through the exit chute while the motor was on low speed). Additionally, the carrier was too high on the area where the threads for the screws are placed. This caused, that the burrs were sitting there instead of the smoothed outer surface of the burrs. I turned both surfaces smooth and increased the diameter of the hole to match the shaft plus 200µm (I had 100µm "feeler gauge tape" (don't know if this is the correct translation, had to google it, kind of "professional shims"))


I also smoothed the fixed burrier holder:


I measured the middle part, and found a large deviation in height. During the processing it looked like this:

and in the end it looked like this:


After assembling, I made the alignment test:


I was satisfied and I am trying out the SSP burrs in the next time.
★ Helpful

Giampiero
Posts: 840
Joined: 8 years ago

#114: Post by Giampiero »

If the lathe is included with this grinder...i'll buy it :lol:

Pflunz
Posts: 139
Joined: 4 years ago

#115: Post by Pflunz »

To be honest, a lathe is quit cheap. If you buy a used one, it is cheaper than the grinder itself.

What I forgot to mention, my grinder has the interesting property, that after adjusting it from coarse to fine, when I want to make a tiny adjustment to grind more coarse (so I rotate into the other direction), the burrs are first getting closer before they increase their distance.

So for adjusting I would advise to always adjust from coarse to fine. If you want to grind coarser, first go really coarse and then adjust finer.

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EvanOz85
Posts: 716
Joined: 12 years ago

#116: Post by EvanOz85 »

Just a few months in, and barely any usage, and the bottom burr carrier is screwed up. The bottom of the carrier is suddenly scraping against the body of the grinder, leaving it unable to gain any usable speed whatsoever.

I've sent a message to the seller on AliExpress, but I'm not expecting much to be honest.

I would caution anyone who is considering purchasing this grinder to not do so for now.

boren
Posts: 1114
Joined: 14 years ago

#117: Post by boren »

Is the variable RPM useful enough to justify getting this grinder over the DF83? I'm debating between these two, mostly for pourover but I'd also like to occasionally use the grinder for espresso. If I go with the DF83 it will be with the stock burrs.

LObin
Posts: 1792
Joined: 7 years ago

#118: Post by LObin replying to boren »

It seems the JT64 with it's small design flaws and lack of customer support isn't worth buying at the moment.

There's a DF64S with variable RPM launching soon, that could be a worthy replacement for the JT64.

There's also the Timemore Sculptor with adjustable RPM and a choice of espresso or brew focused burrs.

I don't do much filter with my DF83 (stock burrs) but some do and have had a much better experience without the declumper. The stock burrs are still espresso focused primarily so you could eventually look at the 83mm brew burr options, Mazzer notably has 2 or 3 affordable models that would fit.
LMWDP #592

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