Who's going to do the math on the force required for the Mac Elle?

Computing brew pressure of direct lever espresso machines

If you're set on this conversion you could possibly swap out the group head with a direct lever. Do you know the bolt pattern of the group head? Generally, the bolt patterns of the commercial groups are bigger than the direct-lever groups but you might be able to make an adapter.

jritorto wrote:I just want to feel it with my own hands. I'm an automation guy by trade, so I (perhaps ironically) bristle at the notion of having machines do my entire job for me and utterly remove me from the process. On this machine, I'm not able to control the lever during pulls -- the linkage detaches during extraction. At design time, an engineer apparently decided that the human should be utterly removed from this part of the process in the name of consistency or something. While arguably good for *bucks, et al, this generally offends my artisan sensibilities quite a lot. But this is just my opinion and of course I do respect yours. We can still be friends even if we disagree and I promise not to carpet bomb your country or anything if we don't share all the same opinions.

Try and find some vids of a busy Italian cafe using a lever and you might understand the reasoning behind the commercial spring lever. No nefarious plot to eliminate the human factor at all, quite the opposite as the barista is usually busier than a one armed paper hanger. The design criteria was to enable a shop to service a line of customers in the pre pump days. And yes, the companies that manufacture these things do want 'bucks' to facilitate continued operation.

It is a wonderful machine, so why not just sell it and get something not offensive to your inner artiste? I think there are commercial lever machines out there with coupled lever assemblies that allow you to 'help' the extraction.

First of all, thanks to everyone for all the advice and support, etc. Secondly, I have to apologise for not telling "the whole truth" at the onset. Confession: I bought this Elle brand new and have used it for a number of years. I've been doing cafe /espresso professionally since the early nineties when I started with a big overautomated and overcomplex Rancilio. So I do know some of the ins and outs of the trade and am well versed in grind, roast, pressure, temperature, long lines of customers, being 'in the weeds,' etc.

So back to the point here: my experience with this brand new spring lever Elle was such a huge letdown because I hadn't done my research back then and didn't even know that spring-lever machines existed. I thought I was getting a real direct-lever machine and felt really gyped. I tried slowing the shots and yeah, that helps a little, but it still smacks of amateur cheesy junk and ten years later, I'm still ticked off. Sorry to be blunt about it to those who favor this sort of equipment. That's just how I feel.

I have a Pavoni, so I know how to pull real shots myself. I simply want a real machine for the business, too. Because coffee is an art form and we care about that. In a rare act of benevolence, I was even thinking I'd even leave one of the Elle's original spring-level groups alone, in stock form, so the newer folks could still handle barista'ing. The Elle is at the end of a wear cycle now and I need new piston rings or whatever causes water drips out of the group when the machine's sitting idle, so I have to decide if I'm gonna just set it aside and buy something I actually want or try to mod the thing. I've already gotten my money's worth out of the investment in this machine, but aside from the silly springs, it's such a good piece of equipment, I see no reason to ditch it and buy new again, especially if they aren't making manual machines anymore anyway.

Oh, and my earlier reference to *bucks was to a well known and highly automated commodity coffee-serving corporation, not to dollar "bucks."

Also, what's the physics for calculating the required pressure? I guess if you have an 18" lever, then that'll exert 150% of the foot pounds you're putting on the end of the handle, at the direct-connected piston rod (inner side of the fulcrum). Then calculate the square inches of the area of the group and just multiply it out to see what's required to generate 135psi at the piston, right?

thx
jake

It might smack of 'amateur cheesy junk' to you, but 'amateur cheesy junk' is the way it's always been done profesionally, and the amateur junk is in fact your La Pavoni, which lacks a spring to save money and save amateurs from getting a lever smacked in their jaw.
So I regret to inform you that your feelings are completely wrong. There is nothing inherently wrong with wanting a springless commercial lever and this thread has provided you with enough options to modify your Elle.

Pressure wise, you should be good, if the lever ratio is enough to compress a spring strong enough to put enough force on a given piston to provide the required amount of pressure, that same lever ratio in a direct connect lever should be sufficient to provide exactly the same pressure with the same piston.

Sounds like you know the machine in question quite well then if you've spent 10 years with it.

Unfortunately it also sounds like you might have some issues in the pull - my judgement entirely though and I could well be really wrong.
You might start off by describing your pulls, what the issues are, what you are missing and what you want to obtain. There are many here that could possibly help you get what you want.

I retard the lever pressure on my Strega when I do lighter loads and lighter pulls, but commercially I'd dial in the espresso differently to run solely on spring pressure. Full pressure shots can be dialed in quite nicely on my lever, and I'd hope the NS Mac Elle could do the same. Actually, shots bordering on ristretto work very nicely in lever machines, although they are slower shots.

If you convert it be sure to document it here, because you aren't the first person so suggest such a modification. Unfortunately there really aren't any fully manual lever machines made for commercial use. My La Pavoni Professional is an obvious exception! Well, at least mine came from a coffee shop in Palm Springs where the owner ran 3 of them for his cafe!!! Absolutely crazy!!!

As far as I know, and correction is welcome, manual lever machines came way after the introduction of the spring lever machine and not the other way around, and were aimed at the domestic market not the commercial.

Plenty of manual machines still being made today, but none for the commercial market. Plenty of commercial lever machines still being made, but still with those silly springs. So name your poison...

The Faemina is but one example of a spring lever with a coupled piston rod. I've got a nice shiny '86 Pavoni Professional that I'll gladly trade for the Elle.

Jacob,

It seems like you have another thing in mind, perhaps, a commercial manual lever, and maybe you have from day one. Somehow this fits an esthetic of the manual pull as an art form. Why not try a DIY project, maybe get a machinist to help you if you don't already have those skills and that equipment, and build a dream group out of the machine you've got. For the quality of the shot alone will it pull any better than one of today's top end non-lever commercial machines? Probably not.

Otherwise, I am taken aback at the idea the classic commercial spring levers of the 1950s are anything less than magnificent works of industrial art.

I've given some thought to how you might do a reversible spring-lever to direct-lever conversion. I think it could be done without modifying any existing parts but it would require fabricating some new parts.

Basically, you could dismantle the group top, take the spring off the shaft, and reuse the piston, shaft, lever, and group body. You would need to build a new lever cap assembly and lever yoke that mimics the design of the cremina/pavoni direct lever group. This should be fairly easy for a machinist to produce.

I think it might be an interesting experiment!