Last time I checked, the thread asks about philosophy, and when a lever isn't a lever. Last time i checked, function was as much part of philosophy (or science, or any kind of knowledge) as form.

Simple definitions, on the other hand, are either just preparatory, or hidden attempts to exercise a specious and unreasoned authority. Let me explain ...

Everyone posting to the thread knows precisely what a classic lever machine is. The reality is that there has been an efflorescence of machines that are inspired by, or derive from, classic lever machines. To ask which of these inspirations or derivations may legitmately be called "lever machine" is boring (i.e. an uninteresting question) and specious (i.e. the public decides what to call things, not you, not the OED, not us on HB, and not even the Academie Francais, although they are legally authorized to do so for French)

The more interesting question, I suggest, is not what to call these lever inspired machines, but what to make of them.

Bob_McBob wrote:By definition, a lever machine needs to have a physical lever of some sort that provides the driving force to the piston.

By that definition spring levers are not levers since the spring provides the driving force to the piston.

jpender wrote:You're basically saying that a lever is defined by an opinion that it is, in fact, a lever.

But isn't that actually the answer? Which is why I proposed the looking through the door test.

Ira

jpender wrote:By that definition spring levers are not levers since the spring provides the driving force to the piston.

No, because the lever provides the force to compress the spring and move the piston. I don't really consider this as much of a philosophical question as the OP. The point is that lever machines are a sub-class of piston-driven machines. Where you draw the exact line is a matter for more technical discussion, but if every piston-driven machine is a lever machine, we're just agreeing to colloquially use the terms interchangeably in a way that makes the distinction unclear for technical purposes.

another_jim wrote:I rather disagree. The mounting popularity of lever machines, along with powered machines with lever-like properties, has nothing to do with their appearance and everything to do with their performance.

There have always been collectors; and collectors are going to be engagged with the physical properties of the machines. But the audience for these collectors is not interested early steam espresso machines, nor curious stovetops, nor in 1970s and 1980s pump machines, etc., etc., but in lever machines. The many new releases of lever and lever like machines is also not about their appearance or physical structure.

All the renewed interest is about the functional properties of levers, in how they make shots and how those shots taste. If it weren't for that, levers would be what they were twenty years ago, collection curios gathering dust.

I reckon that it's both - the increasing interest in levers is both due to their performance which is thought by its adherents to be superior to pump machines as well as to the tactility of a lever vs a pump. The latter point goes beyond a collectors love of tradition and the arcane particularity of trivia. For me, I find a joy in handling a spring lever that is absent from a pump - it just feels so much more satisfying to use the former. There is that feeling that I am directly engaged in actually making the espresso in that I am directly handling that mechanical lever thta is actually pressing out the coffee. I imagine thta a direct manual lever would feel even more engaged.

ira wrote:But isn't that actually the answer? Which is why I proposed the looking through the door test.

Ira

Its like that English judge who defined pornography as basically that he knew what it was when he saw it...

another_jim wrote:Last time I checked, the thread asks about philosophy, and when a lever isn't a lever. Last time i checked, function was as much part of philosophy (or science, or any kind of knowledge) as form.

Function isn't product, though. Function is exactly what it's about - how a lever machine functions.

Cafelat Robot? Sure! Functions as a lever machine.

Machines with no lever? No. They would not be able to function in the same way, whether the produce an identical product or not.

Machine with an internal lever? I will accept on faith that such a machine exists, and it's an interesting question whether the design is functionally valid - whether there's a real lever machine advantage to driving a piston with a motor driven lever, and if so why? That discussion might shed some light on details of the function we're interested in.

A corelary of this question is "when is an espresso a paddle machine"? I think it is when the paddle position makes a difference in the water flowing during the shot.

Using a similar argument I think an espresso machine is a lever when it has a lever that (directly?) I fluences the flow of the shot. Within the set of levers there are different types - manual, spring, etc.

Bob_McBob wrote:No, because the lever provides the force to compress the spring and move the piston. I don't really consider this as much of a philosophical question as the OP. The point is that lever machines are a sub-class of piston-driven machines. Where you draw the exact line is a matter for more technical discussion, but if every piston-driven machine is a lever machine, we're just agreeing to colloquially use the terms interchangeably in a way that makes the distinction unclear for technical purposes.

It was your definition that the lever provides the force. If what you really meant to say was simply that a lever machine has to have a lever I think most people would agree. Your point was made about 50 posts ago. It excludes machines with screws, plungers, and bicycle pumps.

So it's okay if there's a spring that drives the piston as long as a lever is attached. What if the lever raised a set of weights instead of compressing a spring? Or if it compressed air? Or generated electricity to power an actuator? There are lots of ways to store and release energy by pulling down a lever.


Ira apparently doesn't care about what's inside, just what it looks like on the outside. Jim seems to care only about the taste. I personally think that a lever has to have a boiler, so the Robot and original Flair models don't qualify. I'm not sure about the Flair 58 though. It's a border case for me.

jpender wrote:It was your definition that the lever provides the force. If what you really meant to say was simply that a lever machine has to have a lever I think most people would agree. Your point was made about 50 posts ago. It excludes machines with screws, plungers, and bicycle pumps.

So it's okay if there's a spring that drives the piston as long as a lever is attached. What if the lever raised a set of weights instead of compressing a spring? Or if it compressed air? Or generated electricity to power an actuator? There are lots of ways to store and release energy by pulling down a lever.

I think it's abundantly clear that my short definition was intended to encompass spring lever machines, and any other interpretation of the wording is just pedantic nitpicking. Again, the point is that all lever machines are piston-driven, but not all piston-driven machines have levers, so we either acknowledge that the distinction exists or agree to just use the terms interchangeably. It should be possible to define this with a clear technical standard. I would start with something like "a lever, mechanically linked to a piston to pressurize a column of water" and go from there, but it requires qualifiers like whether it should be human-operated, whether a crank is a lever for the purpose of the standard, etc. It's not an insurmountable task.

Personally I think it's very bizarre to require a boiler as part of the definition of a lever machine. Your Cafelat Robot is identical to numerous vintage gravity-fed lever models have always been considered "lever machines". By extension, it also means something like a Decent wouldn't be considered an espresso machine.