DIY Commercial Group Manual Lever (now with videos)

A haven dedicated to manual espresso machine aficionados.
pizzaman383
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#1: Post by pizzaman383 »

I tried manual lever espresso machines but they feel small and unstable in my use. I know that others love them but I couldn't warm to them. So, I went to the commercial spring lever espresso machine and love it. The large, heavy frame with its big boiler just feels so much more solid and the temperature control is very consistent.

However, always reading about manual lever users loving their espresso always kept me wondering. Was there a way to get the best of both worlds? I toyed with the idea of putting a manual lever into a commercial group body but thought it was only daydreaming. That is what it was until I saw a Pro800 listed with a spare spring/piston assembly. A few PMs and a couple of slow covid months later I had an extra spring/piston assembly to play with.

Basically, I reversed the group cap, moved the pivot point in the yoke, and then had to remove a bunch of brass to provide clearance. I am not a machinist so it is kind of a hack job but I think of this as a prototype to test out the concept. If it works well enough for me to use I would probably get a machinist to create a custom yoke

Here are some pics showing the differences and similarities with the normal spring assembly. The machine is now warming up so I'll know later how well I works.


Curtis
LMWDP #551
“Taste every shot before adding milk!”

LObin

#2: Post by LObin »

I'm hooked!
LMWDP #592

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Jake_G
Team HB

#3: Post by Jake_G » replying to LObin »

Me too!

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sonnylowe

#4: Post by sonnylowe »

I will definitely be following this project, I can't wait to see where this goes!! If you need CAD assistance or a machinist feel free to PM me, I'd be happy to help :mrgreen:
LMWDP #597

Giampiero

#5: Post by Giampiero »

I probably did not get the point.
By the photo i can realize that the piston it stand in higher position than an original group right?

pizzaman383 (original poster)
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#6: Post by pizzaman383 (original poster) » replying to Giampiero »

With the spring lever you pull the lever down to raise the piston and the spring pushes the piston back dow. With a manual lever you raise lever to raise the piston then you push the lever/piston down (there is no spring).

This means that I needed to reverse the action of the lever to make this work.

To answer your question the piston moves up and down the same amount after the modification as before. The action of the lever is just reversed.
Curtis
LMWDP #551
“Taste every shot before adding milk!”

LObin

#7: Post by LObin »

3 questions that quickly come to mind:

1. Does the lever fork in it's original configuration allow full motion range of the piston?

When the lever is down in it's new resting position...
2. Are the 4 water inlet holes at the proper height, in between the 2 top seals?

And

3. Does the locking mechanism still engage?
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pizzaman383 (original poster)
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#8: Post by pizzaman383 (original poster) » replying to LObin »

Yes, yes, and yes.

I had to remove a lot of material from both the lever cam fork and the upper piston yoke. As I mentioned this is a prototype to test the concept.

Because this prototype works if there is interest in this project then a well-designed cam yoke is appropriate.
Curtis
LMWDP #551
“Taste every shot before adding milk!”

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LBIespresso
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#9: Post by LBIespresso »

Possibly the single biggest thing stopping me from trading in (putting in the basement) my Cremina for a Bosco/LR24/Lapera is that I hate the idea of leaving the pull to a spring instead of my feel.

I am really looking forward to seeing this project evolve!
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pizzaman383 (original poster)
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#10: Post by pizzaman383 (original poster) »

Well, it works and works well!

I pulled a bunch of fake shots using my puck simulator (a blind filter basket with a hole drilled that is quite similar to the Decent drilled blank baskets which I have as well) to get the hang of it.

The lever moves effortlessly - smooth all the way up and down when there is no puck. You can move it upwards with one pinky. The water starts to flow into the cylinder when the lever is around 45 degrees above horizontal and the holes fully open with a bit more movement. The lever gently falls into the locked up position, if you keep the lever going up. Because the lever moves so smoothly and easily it is trivial to stay near the water holes to control the flow rate into the cylinder.

I pulled my normal two shots (an hour or so apart) and found the results to be very similar to my normal shots. I was not particularly surprised but it was good to see that the machine is still very consistent. It is a hassle to switch the lever assemblies so direct shot comparison takes a bit of effort and time so I am not planning on doing that any time soon.

The manual lever workflow is a little different from using the spring starting at the time when you start the lever downward. You have to pull it down through the whole shot. (Duh, Curtis, isn't that what you were going for? he says to himself :wink:). The biggest difference is that right before the shot hits the weight you want you quickly but gently let the lever up and do the cup swap to end the shot. Then you need to hold the lever down to purge the rest of the water out of the group. This is like learning a new dance step so it is still uncomfortable but I am sure it would become second nature pretty quickly.

As with any manual lever the amount of pressure you need depends on the coffee puck. The heft of the machine and the sturdiness of the group made it feel quite a bit safer than any manual lever I have ever used. I could pull with just one hand but I found that using two hands, locking my arms, and letting my weight do the work by bending/leaning/squatting down during the pull was both very comfortable and easy to control the pressure and ultimately the flow. My machine sits on a higher than normal kitchen counter and that really works well for this.

So, the question is why do this? The answer is that it seems easier to control the pressure/flow when pulling down than either pushing or retarding a spring lever. Matching this with the naked portafilter pressure gauge and profiler seems like a real winner if you are into manual levers. You could choose a Bosco, Profitec, Londinium, Salvatore, or any machine that uses a similar group so you get the manual lever of your dreams!

My plan is to use this as my daily driver for a week or two to see whether I like it.
Curtis
LMWDP #551
“Taste every shot before adding milk!”