F4E is a nice grinder with small footprint, hence high WAF, however the are some features which could be made/designed better (like on any device). I do not like very much floating upper burr carrier supported with springs, which is a bit harder to dial in (the collar) and basically no (accurate) scale. I also suspect it for hysteresis in grinding setting (I think it depends, whether you dial in from coarse to fine or from fine to coarse direction, even to the same target point). I also did not like rough portafiler holder on v1 version, so first upgrades were addressed to apply accurate scale and to replace the PF holder with some more suitable/better one, which allows to hold PF with Tidaka funnel as well as to grind the coffee to a cup on a scale.





Other upgrades were made to modify Compak small hopper to fit F4E and to made "single dose" hopper.





In the winter I decided to improve the upper burr carrier to my liking with aiming to make the setting more accurate and easier, and to lower the grinding chamber retention. Based on the Mazzer Mini successful burrs upgrades to 64mm, in the first step I modified both carriers to 64mm burrs (good starting point, but only side effect of intended modifications ).




Once the 64mm burrs were successfully tested, I knew I can use them in the final project. Whole upper burr carrier system is designed from the ground up. Whole system can be removed for cleaning without losing the setting. It's very accurate, easy to dial in and also has a unique* lock feature, which not only locks the setting, but also removes any upper burr play, if ever any exists (* I don't know about similar function used in other grinders). It also effectively lowers the grinding chamber retention (space above sweepers).








Based on the features I think the new upper burr carrier system is on par with much more expensive grinders (even in high end class). If I were thinking to make my own SD grinder, half part of the grinder is ready yet.

Is this end of the project? Hmmm ...

Peter, congratulations on your completed project and wow, your mods look very oem. It ups a good grinder to the next level addressing a few points. 1) Larger burrs and sweep arms lowering retention and decreasing grind time. 2) Ability to clean burrs without losing previous setting and removes carrier thread also reducing retention and a locking device as a bonus.

Is the black adjustment gear plastic or metal ?

Rob, it's a plastic one. I decided to use it to simplify the manufacturing - yes, I know the metal one would look nicer . It perfectly matches the worm screw.
Dialing in is very easy and accurate, small changes (1 step, maybe more) can be done even without grinder running.

Seems like the plastic gear does the job.
Reminds me of the adjustment mechanism on the ECM S-Automatik / Profitec Pro T64 grinders.

This plastic gear is Macap . Why not to use ready solution? However, it's a separate part, so can be replaced with custom made metal one anytime later, if I find somebody able to make it (but I'm pretty sure except of better look it's not worth to make it).

Slightly OT... is the platform used to weigh shots, with the scale under the drip tray, custom?

Amazing work.

Yes, I did it.

redbone wrote:Peter, congratulations on your completed project and wow, your mods look very oem. ...

Thank you. Btw, project is not completed yet, there are still some features worth to upgrade . I'll keep you posted (once they are ready) .

Looks great Peter! Nice improvements!

Very Nicely done Peter.