thanks adam and patrick - i will try a better penetrating solution (i am using inox, which is better than the wd40, which i don't have - just seem to call the inox wd40 out of habit....) and i already have started on a special wrench.... i will post tomorrow or as soon as i get it off or swear too much.
cheers!

the lower chrome ring of the microcimbali is reluctant - after a few days of applied inox, heat applied to the chromed bronze (or brass), and a special-made wrench, with which i hammered the lever, it is still stuck....
i will continue soaking it, but worry that it is not a screw-out, that perhaps i have missed something obvious.... in the meantime i will source some specific penetrating oil, in case that is the problem. but after heating, i really thought it would have loosened just a little!

Can you see anything thru the viewing window, perhaps with the spring compressed?

It would be nice if you could see some threads on the inside or even get some penetrating oil on the inside thru one of the ports or thru the window somehow.

BTW, nice job on the wrench.....

adam, thanks for the thoughts - you can see that there may be a thread inside - there is corrosion and it is in a hard place to see - i am looking at it with a small mirror and flashlight, but the spring is getting in the way of course. i have been spraying up there too, but if it is a thread, it is large and long - would be hard to undo normally.
i have removed the seal with a jeweller's saw and pin and tweezers (mad), so that the seal is 75% gone, and i have been spraying in from there. obviously the oil wasn't getting in because it was sealed there, so it was good to get access to the threads (if threads they are). will soak for a few more days and give the occasional nudge. if not, i will heat it and spray as it cools, and then possibly give up (unlikley), or soak it for a week in a puddle of kerosene.
stubborn!

...and i have been reading up on galvanic corrosion between the brass and aluminium - it seems they respond quite well to each other and create a wonderful condition for the formation of oxides. put it all under pressure with crap from the local water system, and a huge thread area, after 40 years, and it becomes quite problematic. i think this is why the later models all used a different construction method in this area, three bolts to the body in stainless steel. much smarter.
i will keep heating and adding penetrant oil, but it seems like it may be a lost cause. eventually it may just be a personal lesson to never use such dissimilar materials together in a situation under constant heat expansion and soaked with tap water....

last post on this thread - promise. got the beast undone - a large fine thread with lots of corrosion on the aluminium body side, as expected. heated it, sprayed inox as it cooled, heated it, sprayed, heated it, sprayed, and with some liberal force it started to move. the bronze is strong - it didn't deform, so the portafilter still goes in....
this machine is different to all the other microcimbalis - the whole head and piston body are a single solid unit - very heavy.





i am now up to finding the seals - two u-cups on the piston and a u-cup and flat rubber at the top where the piston rod exits up through the boiler. i may have troubles with some of them - i will measure them up and start looking.

thanks to all who suggested and encouraged - i feel much better now - especially seeing the crackly state of the seals - definitely in need of replacement! i think that the condition of the boiler inside is not too bad for aluminium, so it seems it has sat somewhere unused for many years. full post of tear-down coming soon....

Excellent thread. Thanks for the pics and details - it's sure to help others. Maybe myself as I have access to a Micro in need of restoration. At $200 it's worth thinking about I guess.

don, not sure i would go for a restore now if i had to over again - the aluminium boiler is really starting to bug me - such gross material. the microcimbali looks great, and i am sure it will make a good espresso or two, but as a permanent machine for everyday coffee - i am not sure....
though from your list of equipment don, i see you are an addict - there is no cure!
i have learnt heaps just pulling it apart, so it was worth it! i am on a mission to pull a few other machines apart and restore them, as i want to learn as much as i can before embarking on a ground-up design and build of an open-boiler stainless spring lever - small but potent. ambitious. but in the meantime, time to get smarter!

(oops - another post - i can't help myself....!)

albert paca wrote:(oops - another post - i can't help myself....!)

Good threads go on and on so be flattered .

As far as the aluminium head and boiler assembly is concerned I'm really interested in having the whole thing recast in brass or bronze. I have the ways and means and it won't be all that costly as a one off. Whether or not I ever get around to it is another thing.

After reading this thread I don't think I would bother with the MicroCimbali as a stock restoration.

Good job Sean; glad to see the persistance paid off and nothing was damaged