Sloppy grinder housing thread: alternatives to Teflon tape

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florianzzz
Posts: 4
Joined: 6 years ago

#1: Post by florianzzz »

Hi all,

After playing around with a problem I am encountering with a grinder (Macap M4d) and tried to find solutions on this forum (not successful), thought made sense to start short topic for future reference. Willing to try soluions (and post results) Anyway:

Problem analysis:
- On my minimum/finest setting of the grinder, the grinder grinds too coarse. Problem is with grinder - not coffee (fresh) nor machine
- Marker tests indicate that the burrs are aligned perfectly (under no coffee pressure obv)
- Screwing in the top-burrs into the housing, there is a a little bit of play: able to move the top part (that you screw in) a tiny bit

Solution that worked so far:
- Teflon tape! When taping 2 layers, the top part screws in more difficult and play is gone
- But it does result in perfect grind! (hence - found the problem)
- However..

Downsides:
- After 4/5 grinds the teflon tape solution is not working anymore. It shreds off/dissolves
- The grind is too coarse again
- Need to repeat the teflon method

The ask:

- did anyone experience similar problems?
- are there more structural ways of removing play between the threads? Alternatives to teflon that can/will stay longer? More static solutions?
- Or is my problem analyses not accurate?

Would hate to throw away a - else - good working machine. However, perhaps, just like cars, the machine is economically totalled..

Many thanks for ideas and help!

ira
Team HB
Posts: 5497
Joined: 16 years ago

#2: Post by ira »

Are you saying without the teflon tape you can't get the grind fine enough? If you turn on the grinder and then while it's running adjust the grind finer, can you adjust it till the burrs just touch? If not, something is not right as I don't remember any stop in my M4D that would keep it from getting much finer than necessary. If you can't get the burrs to touch, figure out why as that should solve the problem. Normally when grinding the beans push the burr up and remove all the slop, so while it's not optimal, it should not cause a problem.

florianzzz (original poster)
Posts: 4
Joined: 6 years ago

#3: Post by florianzzz (original poster) »

Wow, I never thought about thread slop as something that solves itself under force. Super helpful, thanks. Will play around with turning it finer under load and report back

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mrgnomer
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Joined: 18 years ago

#4: Post by mrgnomer »

Depends on which threads are off. You could try new bolts if those are off. If it's the female threads in the chamber you could cut slightly larger threads in and use slightly larger bolts.

Top and bottom burr bases are usually made of aluminum and can get damaged from cross threading or over tightening. You could go commitment fix and loctite them. If you go with the strongest loctite you might need an impact wrench to get them loose down the road. Med strength loctite would be potentially easier to remove.

There's gas line teflon tape which is more expensive but thicker than regular plumber's tape. It could hold where thin teflon doesn't.

Stock burrs should be engineered to touch at a finest setting. After market, maybe not. I 'upgraded' to 64 HU SSPs for my Ceado e37j and wouldn't you know it, couldn't get the burrs to touch. The SSPs are about .5mm less in thickness than stock. I'm putting plastic gaskets as shims underneath both top and bottom burrs to lift them up by about 1.6mm total. Still working on it. Hope it does the trick.
Kirk
LMWDP #116
professionals do it for the pay, amateurs do it for the love

Pressino
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#5: Post by Pressino »

I don't know how the Macap grind adjustment collar works, but in the Mazzers there are springs that exert force that pushes the upper burr holder against the threaded collar (or vice versa if you want to look at it that way) which reduces the collar's "thread slop". If these springs weaken (e.g. from long use), the force they exert on the collar becomes insufficient to prevent thread slop. The solution is to replace the weak springs with stronger ones.

florianzzz (original poster)
Posts: 4
Joined: 6 years ago

#6: Post by florianzzz (original poster) »

Thanks all for the super helpfull messages. The solution was combining the slightly thicker teflon and reducing the courseness of the grind "under load" (with beans grinding). Burrs touching point is different without beans.

Kinda made me feel like an idiot, but at least an idiot with a proper espresso!

Thanks all for the help, truly appreciated! :)

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mrgnomer
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Joined: 18 years ago

#7: Post by mrgnomer »

The shims seem to be working after a month. A bit of shift to finer in the grind setting from newly installed but that could be from a lot of things. The grind setting it's settled on is pretty fixed and consistent across a lot of different roasts.

Macap M4 does work with springs and it's pretty easy to get clean running burrs to touch. I use a grease pencil to mark the zero point for reference and then the grind setting range when it's dialed in. The gear tooth collar can be repositioned but there's no guarantee of setting it to a dead on marked zero point making numeral readings for grind fineness relative to the start of the zero point.

The Ceado E37J uses a spring steel spacer. Zero on that grinder is to the point of compressing that spacer almost down to flat. There's a lot of resistance and it makes collar adjusting really stiff. I see it as a design sacrifice to be able to easily remove the top burr carrier without losing grind and zero point setting.
Kirk
LMWDP #116
professionals do it for the pay, amateurs do it for the love