Very interesting indeed, Jon. I still think there's a good chance this is an issue with a shifting gasket, but of course I see your points and I readily admit you're the real engineer.

You should come over for coffee, since you're close. I don't have a whiteboard, but I do have white paper and pens...

shadowfax wrote:You should come over for coffee, since you're close. I don't have a whiteboard, but I do have white paper and pens...

Paper and pens will work!

Let's try to get together this weekend, OK? I have some honeydo's at home but should be free at some point. I have some new coffees we can try if you like too (Jon's L.V. lives again...smoooooth and creamy)

Jon... I think you were agreeing with me? I tend to agree with your point at least (also being an Engineer) that it is not spring in the metal components that would cause this... but I would say it is the compression of the gasket that would allow the rotation... i.e. the portafilter theoretically rotates about two (far to small) contact points between the ears and the group and compresses the gasket (the section near the portafilter handle) and exposes a gap between the basket and the gasket on the machine side. The point about being enough room to rotate in the group head groves... good point, but I would guess there is, just from examining both of my machines it seems like there is plenty of play radially around the portafilter.

Obviously we know that a gap is opening up between the gasket and the basket/portafilter (the basket can't gap unless the portafilter gaps too), and we know that the handle is moving up (which can only be rotation, assuming the ENTIRE machine is not moving up) so to me, it seems like some sort of rotation must be taking place... just my guess though

Karl

PS. I was not dropping the engineering card to more legitimize my point (my point hopefully stands on its own without an appeal to authority) just trying to open up the conversation for more well explained technical discussion if the problem warrants

karl_a_hall wrote:Jon... I think you were agreeing with me?

I think we can all agree on that. The gasket does have to give a bit also if the portafilter pivots.

What I was saying about copper is that it's very soft and if you dent it then it stays dented....so if (for example) the groove has high and low spots then the portafilter ears could lose precious contact area. In the worst case, the contact becomes a point on each side and creates an axis for rotation.

Then the clearance of the groove allows the portafilter to pivot far enough to break the seal.


Does anyone else thing the grooves look wallowed or worn? It seems to me the chrome is gone from part of the groove, and this may be an indication of wear in that area. Besides being easy to permanently dent, copper is also easy to shave off (and it's free-machining - very easy to drill and cut)

John - the group on this machine is all brass, including the groove. I did not think it looked overly worn from the pictures. Copper on these machines is only a thin layer (some kind of electrochemical coating) over steel on the upper case.

I also believe it's possible the pressure builds in the portafilter and it moves, pivoting on the wings (this is what I tried to say earlier, Karl said it better).

So I guess a new portafilter should solve this. I'll ask if I can return it if it does not solve the problem.

Joep, over here, the least expensive portafilter that fits the Elektra well is a Rancilio. Not fancy, but nice heavy brass with a good plating. About $55 without a basket, you may be able to do better from the Netherlands.

Just curious, what part of the Netherlands? My father was a commander at Soesterberg (near Utrecht), I enjoyed my visits to the Netherlands very much.

Enjoy your experience, James

Indeed, groupheads, pipe fittings, and portafilters are generally made from brass (with the pretty pieces being chromed) rather than copper, or they wouldn't hold up at all. I believe it's only boilers themselves and pipes that are copper, and even on those the contacts (threaded fittings, compression ferrules) are usually machined brass that is brazed onto the copper. I am not hardcore into metallurgy, but I believe brass is a pretty hard metal--not stainless steel, but way better than copper.

I'm not convinced about the portafilter that is the right one for the MV
I know it is different from the standard elektra one
I'll be talking with elektra again tomorrow
to confirm or not now that we have more pics
honestly in almost 10 years of repairing machine I've seen only 3 mini verticale so I don't have the details fresh in my head
however I can tell you that the commercial portafilter will also work but it will go past the 6.00 o'clock point
see you tomorrow

My portafilter goes VERY far to the right. Without the spacer ring installed it turned to about 8 o clock before it was tight. (with the blind filter installed, flatter top I guess, even to 8:30)
No with the spacer installed it turns to about 7 o clock (7:30 with the blind filter)

@ James
I don't live very near Utrecht. That is, about 80 km away I guess. That's very close in the USA, but not really for Dutch people. Utrecht is central, I live in the east. Yes, it's that small haha.

Looking forward to your answer, Stefano!

shadowfax wrote:I am not hardcore into metallurgy, but I believe brass is a pretty hard metal--not stainless steel, but way better than copper.

Technically speaking, "Brass" is any alloy containing copper and zinc. There are something like 300 recognized alloys called "brass" and probably 2 dozen of those are commonly available and used for most applications. None of these is particularly "hard" metal (relatively speaking) although it's true that brass is generally stronger than straight copper.


EDIT - This thread is way too entertaining!


EDIT2 - MY APOLOGIES! Looks like I am WAY off for the number of copper alloys (apparently there are well over 2 thousand copper and copper alloy grades including brass and bronzes)

Wait are we reading the clock the same way here
that confirms my suspicion about the portafilter it should arrive easily ( for a used machine to 6 oclock)

Uhh,oops!

Wrong way around.
With filter without spacer: 4 o clock
Blind filter without spacer: 3:30
With spacer, fliter: 5 o clock
With spacer, blind filter: 4:30

Sorry.

It just goes very far to the right. Like this video on youtube shows. That was in my first month of use. Yes, I left the portafilter in the group head way too long before I started the pump. I didn't know that yet at that time.

Yeah Jon, 300 is a bit low there are something like 20 categories of brass alone, let alone bronze

I am very hesitant to say that brass is 'hard'. It is actually more malleable than copper if it has less than 45 % zink (i.e. it deforms without rupture better under compression than copper) and really is quite soft, especially compared to stainless. Brasses are between say 35-65 HRB (Hardness Rockwell B scale) and even annealed stainless (like 440) is at something like 80-90ish, which is work hardened to what 115-130 HRB? That is a pretty big difference... therefore I think Jon is right about the plastic deformation (what hardness measures) of brass would lead to less contact between the ears causing this sort of thing (assuming it is not the portafilter)

Although it very well could be just a wrong portafilter, causing the same thing.

I do find this quite fun too! Never thought I would pull out the Metals Handbook to reply to a thread... but alas that day has come (just to double check my numbers though)

K

Edit: Shadowfax... You are quite right though, components are made of brass because it is harder than pure copper, actually brass is a solid-solution alloy of less than 37% zn in order to increase hardenability by preventing crystal plane dislocations without worrying about second phase brittleness of copper. There is the metallurgical explanation for you.

karl_a_hall wrote:There is the metallurgical explanation for you.

Sweeeeeeet post

JonR10 wrote:Sweeeeeeet post

I do love it how sometimes we even get to talk about coffee

Didn't forget about this post I'm still trying to talk to the right person in Elektra
that has been out of office for couple of days
again my suspicion is the portafilter I'll get a second opinion on monday hopefully

Thanks, looking forward to your answer!

Also for the Elektra tech -- the portafilter wing looks worn and too rounded
and ALSO the group head bell shows a lot of wear
I would start by replacing the portafilter ( less expensive) and see

Hi Stefano,

Thanks. So the portafilter IS a (worn) Elektra one, or not? Well, I'll buy a new one and see what happens. Thanks again!

Joep

Wow, new portafilter is 75 euro. I expected more like 50 euro.
Well, it's necessary, so I guess I'll have to do it...

Wait until you see how much a replacement group bell costs.

Make sure you have wiped off any stray grounds from the portafilter ears and basket rim before you lock you portafilter in. The coffee will act like sandpaper and wear the parts much faster.