Building a lever machine.... from scratch - Page 3

A haven dedicated to manual espresso machine aficionados.
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bidoowee

Postby bidoowee » Jun 13, 2016, 3:34 pm

Yes indeed. I've seen these. Essentially an upscale version of what Dominico made.
Useful for diagnosing problems with pump machines as well.

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pootoogoo

Postby pootoogoo » Jun 13, 2016, 5:57 pm

Nobody here to say how awesome is that group replica. :shock:
This is incredible... if I break one of mine, I'll just have to do the same. :roll:
Just joking, it takes a lot more than what I'm up to, but I'm curious about how much this whole operation could cost.

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bidoowee

Postby bidoowee » Jun 14, 2016, 9:50 am

Hi Pootoogoo,

Thanks for the encouragement. The are several brief answers to your question: I don't know, too much and it depends ;). I won't really know how much this will cost until all the parts are actually made (by me in some cases but mostly by other suppliers) and delivered. What I do know is that is is waaaay too expensive to consider making only one. Casting is a good method for making multiples but getting it all set up is labor-intensive and costly. It would be possible to machine a single unit out of solid stock, but again, the cost would be much higher than the value of the whole machine. Finally, the cost is dependent of course on volume. Based on my estimation, making ten or so will result in a slightly higher cost per unit than buying something comparable from a reseller. Making a hundred changes that substantially... And of course, none of this is counting my time.

Bidoowee

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bidoowee

Postby bidoowee » Jun 14, 2016, 10:55 am

Over the last few weeks, while I have been waiting for the foundry to setup and make the first casting, I have been converting a lathe to CNC in order to fabricate some parts in house. This seemed sensible for a number of reasons among which is prototyping, which is expensive to have done, but possibly also for some small-volume production. The plumbing parts for the boiler are good candidates as they are expensive and in a few cases impossible to find. Additionally, the ones that I can purchase from my local supplier (and from what I have seen online) have no material certification - which means that they may or may not contain lead.

So yesterday, after close to a month of modifications and wrangling new software I started cutting my first part: the lever handle.

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This is just a piece of hot-rolled steel that I had lying around. I will be using cold-finished 1018 steel or I may switch to 7075 aluminum if I can find it cheaply enough here in Canada.

The first couple of passes taking off the nasty foundry scale before preparing one end of the stock.

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Roughing passes on the straight and conical parts of the handle.

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Today's goal is to try to finish the profiling and threading.

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bostonbuzz

Postby bostonbuzz » Jun 14, 2016, 2:56 pm

Damn, nice job machining that lever handle! I Yearn for the days when I lived 2 blocks from my neighborhood maker space/machine shop.
LMWDP #353

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bidoowee

Postby bidoowee » Jun 14, 2016, 3:36 pm

Thank you!
Yes, maker space/fab labs are fantastic resources. I wish I had one near me.
A month is a long time to spend building something in order to build something else!
However, it is great now that it's done. It opens up a wide range of possibilities.

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drgary
Team HB

Postby drgary » Jun 15, 2016, 1:54 am

Fantastic project and thread, Thomas! I'm marking this as a FAQ because of the detailed discussion of casting and machining a group, just for starters.

To the issue of lead in the group contaminating the water path, are you planning to chrome plate the cylinder to shield some of that and increase durability?
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

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bidoowee

Postby bidoowee » Jun 15, 2016, 9:20 am

Hi Gary, thank you on both counts!

That is a great question. I only started becoming concerned about the quantity of lead I've been consuming in my morning coffee over the last fifteen years when I started doing the research for this project. Unlike leaded gas, leaded brass is still very much in use. In fact, my regular supplier here in Montreal only has leaded brass. They hadn't heard of any of the possible lead-free alternatives and after making some calls, they told me that they couldn't get them for me from their suppliers. It turns out that there aren't that many suppliers at a retail level even in the US but I did eventually find one.

I don't have a good photo on hand, but a close examination of the interior of the cylinder and the piston of the machine I have disassembled shows the tell tale signs of dezincification where the chrome plating has worn off or was never present. This will occur to all brass alloys to some extent, but their are a bunch of elements that can be added in trace amounts that will slow the process by at least one order of magnitude. The bad news is that among the favorite additives in old school alloys is arsenic! The good news is that the alloy I am using has phosphor and silicon and that these work as well or better than the tradition, rather more toxic choices.

So the interior wall of the cylinder of the new group is chromed, because the outside is, but purely for aesthetic reasons. The piston however wont be because the alloy I have chosen is resistant to dezincification and contains less than 0.3% lead in any case.

The question that I haven't answered yet is how thick the chrome plating actually is on the various parts of the group. So called show chrome is the process used to coat motorcycle and car fenders etc. Hard chrome, which is merely a much thicker layer of chrome, is used on wearing parts subject to high loads like shafts. I was wondering if anyone knows or has measured the plating thickness for the body of the group or the lever fulcrum for example?

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espressme

Postby espressme » Jun 15, 2016, 10:04 am

I have been following this for a while...Thank You!
As to plating:
The first layer from the substrate will be a copper layer which bonds well to all the metals in use.
Next would often be a fairly thick nickle layer;
Then a relatively thin chrome for wear resistance, protection, and looks.
The older machines (5) i have dealt with stopped with only the nickle plating and did not use chrome plating.

And, yes the pitting through the plating in the boiler and pump was significant. Probably due to less than pure water which allowed constant electrolytic action between dissimilar metals of the assemblies. Zinc/pot metal pistons were the worst offenders! Bye the way, de-ionized water can be worse of all for corroding metals.
Just my opinions, check with others to verify the information.
~Richard
richard penney LMWDP #090,

GreatDane

Postby GreatDane » Jun 15, 2016, 2:36 pm

I am enjoying watching your build. What a beautiful lever machine! I am hoping that you will be able to offer machines or kits for sale in the future.

Les
LMWDP #079