2: Four Generations of Group Heads - La Pavoni Lever Espresso Machine

[@jannsander]

Most people might not even notice that this exists but passionate (and talented) people like you are such a valuable addition to every community, especially community's like this!

[@JohnMichaelHauck]

Thanks!

[@nachoote260]

John, your work with these models is just outstanding, and a jewel for the whole Europiccola community.

[@JohnMichaelHauck]

Thanks!

[@BrucePappas]

Wow! I am blown away! First time we've had a look at all 4 generations of LP groupheads. Well done and very good explanation!

[@ernieburgos7702]

Thank You. Outstanding work you did to help educate the La Pavoni LeverHeads. Much appreciation for all your effort in this endeavor.

[@tolga1cool]

This is absolutely amazing! Great resource!

[@mooriginal]

Respect to you fella.

[@peegroothuizen5150]

Fantastic to see the differences in 3D! I would have liked you to go into the brass sleeve, shower screens and portafilter dimensions a bit more.

[@JohnMichaelHauck]

Pee, Check out bit.ly/LaPavoniCadGuide From there you can learn how to open the CAD model and measure everything interactively. Let me know if you have problems getting this to work.

[@0xC4FE]

great work

[@JohnMichaelHauck]

Julian, Many many thanks!

[@oxdudepoege]

@John Michael Hauck, are you aware of that the group head side bi side overview isn't public available anymore if one uses the shortlink?

[@JohnMichaelHauck]

Thank you, I was not aware of this. It should be public again. bit.ly/LaPavoniHeads

[@timothypiper6215]

Do you know if a new Gen 3 head would fit a Gen 2 machine. Amazing video thank you

[@JohnMichaelHauck]

Yes. In fact a Gen 4 should fit a gen 2 boiler as well.. Here is a link for a new Gen 3 group head: coffee-sensor.com/product/la-pavoni-lever-complete-q-grouphead-assembly-chrome-code-3940042/

[@timothypiper6215]

Thanks so much John

[@Dinijsv]

Hi John, thank you very much for explaining the differences between the generations! Do you have any more insight about the 4th gen (Stradivari) group head performance? Does the extra weight have an impact to the temperature stability?

[@JohnMichaelHauck]

I've not noticed a big difference that the extra mass makes. I'd like to quantify that someday.

[@Koffiekliniek]

Hi, I would just like to add that the v1.x group is screwed into the boiler, and not welded. So, removal is possible although a bit tedious.

[@JohnMichaelHauck]

So like a large pipe thread? That makes sense. How do you attach the siphon tube? At the same time you thread the group head?

[@Koffiekliniek]

@@JohnMichaelHauck yes large pipe thread. Francesco Ceccarelli showed how the group was screwed on the boiler. You could remove it by swiveling the base and putting a large pipe in the grouphead to use as a lever. I don't know about ths siphon.

[@massimilianomirabello8505]

Hi John, great work! It explains a lot. Could you also explain what happens when you lift the shaft and the portafilter with cofee is on? I expect some air coming through the portafilter and the coffee being trapped above the water. I think this air steals some space from the water (reducing the shot volume) and makes the shaft spongy when you push the lever down.

[@JohnMichaelHauck]

Massimiliano, you and I share the same understanding of trapped air and spongy pulls. I wrote up my thoughts is two places: facebook.com/groups/lapavonienthusiastsgroup/posts/512743113415984/ and here www.home-barista.com/levers/trapped-air-spongy-pulls-again-t76728.html

[@papajohn7779]

Massimiliano, since I've started lifting the shaft almost to the top before attaching the portafilter, I've had the best crema ever. It takes a bit more dexterity with one hand on the lever pulling up and the other hand holding down near the drip tray, but it's worth it!

[@pirminborer625]

Amazing work! What nice models. Are the diameters of the lever shaft of 3rd gen accurate so I can base myself on it to make a pressure profiling kit ?

[@JohnMichaelHauck]

You are welcome to view the CAD models at bit.ly/LaPavoni I cannot provide any assurance of manufacturability. There are so many variables to consider. For example, there are variations in production, so any measurements made on one part does not capture the tolerances of a real product. Also, I used a digital Vernier caliper without formal training... so well there you go. I am open to any community feedback that can help improve these models.

[@guillaumefortinmoquin2875]

What is that cad software you are using? looks nice to use

[@JohnMichaelHauck]

Guillaume, I am using the cloud-based CAD at www.OnShape.com I really love this product and would recommend it. You can view this CAD model interactively online. Start here to learn how it works bit.ly/LaPavoniCadGuide

[@elisilver97]

So cool to see the progression both internally and externally! Is the CAD publicly available? When i tried, the links were dead.

[@JohnMichaelHauck]

Eli, I hope the links are not dead! Try this for the guide: bit.ly/LaPavoniCadGuide This is a direct link to the model: bit.ly/LaPavoni

[@jackaw1197]

@@JohnMichaelHauck For anyone else who has problems - The links are case-sensitive (perhaps it would be good to put them in the description)

[@rastislavstanik]

excellent!

[@JohnMichaelHauck]

Thank you! Cheers!

[@eldavo5168]

Awesome CAD models, any renderings in Solidworks you can share?

[@JohnMichaelHauck]

kzbin.info/www/bejne/pXnbe2SAjt11fqM kzbin.info/www/bejne/gX2lcoNulLiSeNU instagram.com/johnmichaelhauck/

[@Anarchsis]

Can you add a spring into the group head? Also could you add a valve to be able to pull back -to-back shots? Just two absurd questions I had.I have a Gen.2 La Pavoni and a more recent Professional.

[@JohnMichaelHauck]

You ask, "Can you add a spring into the group head?" Interesting! Well, then lifting up the lever would require a fair bit of effort to compress the spring. You might be lifting the machine off the table. The spring-lever machines I have seen have the handle the other way so pressing down compresses the spring. In any case, I think the spring would prevent the piston from going up high enough to let in the water. Other than that, I think it might work. I've never heard of anyone asking this before. You ask, "could you add a valve to be able to pull back -to-back shots?". Honestly I am not sure what you are asking. If you mean raising the lever to run another pull of water through the same puck of coffee grounds, then you can already do that. It creates a vacuum when you raise it immediately after pulling a shot. That vacuum may or may not destroy the integrity of the puck. I'm sure you can get strong opinions on that either way. I've done it before. Some manuals say you can do it too. If you mean something else, then let me know.

[@Anarchsis]

@@JohnMichaelHauck Thanks for your reply. The second question needs clarification. On the automatic lever machines, most have a 3 way valve that allows them to take the portafilter from the group head without waiting 30 seconds or so before reloading another full basket, on a La Pavoni there is the traditional time lapse before you can pull your next shot, in the automatic machines there’s a 3 way valve and a bleeder tube that releases the pressure in the group head that releases water so that the portafilter can re-loaded. So could a 3 way valve and bleeder tube be fitted to quicken the time between shots in an LP? I have an LP and am interested in it’s mechanics.

[@JohnMichaelHauck]

Ah! Taking the portafilter off early on a La Pavoni can result in, what many affectionately call "The La Pavoni Sneeze". Some of the "after" photos are truly works of art. In any case, you can reduce the backpressure immediately on a La Pavoni by simply lifting the lever about half way and removing the portafilter while the maintaining the lever in this position. Why does this work? Understand that there is always some compressed air trapped in the area below the piston and above the coffee grounds. Raising the piston half way increases the volume of the area, reducing the air pressure. Another option is to use techniques to reduce the amount of trapped air to begin with. My opinion (hotly disputed by others) is that by flushing hot water through the group head before attaching the portafilter will help reduce the trapped air. Why does this work? Because it helps the initial hot water that enters the area to "flash vaporize" (Google that term) into steam - driving out the air through the ground coffee. Of course, that means you are brewing with hotter water which may make the shot taste a bit more bitter. Finally, some people are experimenting in using a "pressure profiling kit" to bleed air from under the piston through the piston rod. Sheesh that was a long reply.

[@Anarchsis]

@@JohnMichaelHauck thanks

[@dennisman7775]

Hey, could u please explain the water coming in through the holes in greater depth please? ty

[@JohnMichaelHauck]

There is some more detail in video "#13 Flow & Temperature Simulation" kzbin.info/www/bejne/m4LYdo16jpt0rdE If that is not enough, let me know in a bit more detail what you are looking for and I'll try to address it.

[@novoum]

thank you

[@JohnMichaelHauck]

You're welcome

[@leighp03]

thankyou for this, you answered so many questions about my series 2 group, my Q how did you make the piston move in this cad? Love your work mate :)

[@JohnMichaelHauck]

In CAD, there is a concept of a "mate" that connects parts together. They restrict movement between parts. OnShape names their mates: fasten, revolute, slide, planar, cylindrical, ... You can learn more here: cad.onshape.com/help/Content/mate.htm. I allow the piston to move by not using a fasten mate, but rather a slider mate.

[@dparham]

are 2 and 3 identical on outside? they look to be

[@JohnMichaelHauck]

The diameter of the top part of the generation 2 group head is 50mm, while generation 3 is 60mm.

[@dparham]

aahh ok thats the pre and post ones right? @@JohnMichaelHauck

[@dparham]

ahh ok mine is the 2. ... what upgrades can be done to the 2? I refinished it in ferrari red and chrome and added the boiler pressure ggauge and a cafaleta portafilter/IMF basket and silicon gaskets a few years ago but it always gave me issues like seizing up with handle up... hard to pull shots.. and just total inconstancy.. but ive decided to get it back out and work out these issues... usually im working on more commercial units but this one befuddled me until I saw your cross sections.. now Im curious!

[@JohnMichaelHauck]

@@dparham Generation 1 started around 1961, Gen 2 was 1975, Gen 3 was 2001, and Gen 4 was 2005. People call the Gen 3 the "post mil". Gen 4 is also after the millenium, but I think most people call that the Stradivari instead. "Pre mill" seems to refer to Generation 2 only. Generation 1 is also before the millenium but frankly seems like it is no discussed much. Personally, I just use the generation numbers. Finally, both Gen 3 & Gen 4 are actively being manufactured.

[@JohnMichaelHauck]

@@dparham As for your Generation 2, it is not clear to me when you mention hard-to-pull shots, if it is a mechanical issue or an issue forcing the water through the ground coffee in the portafilter. If it is mechanical, my guess would be adding some lubricant to the inside of the group head and on the two piston gaskets. Search for a high temperature food safe grease. It it has to do with forcing water through the puck, the following will make it easier: grind coarser, use less coffee (13g), brew when the group head is cooler, don't push the lever too hard - being patient to let the water get through, and use older beans. As for upgrades to the Generation 2, the most helpful is what is called the "Bong Isolator" available at www.coffee-sensor.com. Here is a link to the product: coffee-sensor.com/product/bong-isolator-and-water-heated-grouphead-mod-for-la-pavoni/ You can also chat with the inventor (Bong) and the owner of Coffee Sensor at facebook.com/groups/lapavonienthusiastsgroup as well as people who use those products there.