The C'lever Project: Building an espresso machine from Cremina parts - Page 2

[TUS172]

Thanks Greg,

I'll just use the bottom of the boiler to get a template for the hole pattern. But it is great to hear that you have already done the replacement of a heating element into one of these units. What type of bolt-in element did you use, how long was it in before it burnt out and what was the wattage?

I figured on the .25" hole for more of a secure and flush fit. Even the Pavoni professional heating elements have a small recess to fit in the fuse. Perhaps a quarter inch is overkill maybe an eighth would do.

The Knob on the steam tap that I have now is in rough shape... whoever owned it previously must have thought by tightening the crap out of the machine screw in the cap it would stop a leak... so it is cracked on the interior. I am going to try machining the boiler cap out of brass and another out of stainless so I may do the same for the steam tap knob. I am not sure yet because if I do the cap and knob in brass and stainless what am I to do with the lever handle? I guess I could go black...

[mogogear]

I will have to look up the element type again- I think it was for a Carimali, 1000w, it was about $40. The depth of the recess is just not a big deal - the deep well on the Oly was to have the thermostat as close to the loops of the element as possible. On the new type element the coils actually touch the base. So having the externally mounted Thermostat just in contact with the outside of the base plate is sufficient.

Choosing an element that has coils as close to the base as possible will keep the transmission of high temps as spontaneous as possible. The depth of the screw holes needed to retain the thermostat is the bigger depth issue with the thickness of your base plate material. My coils are with in a 1/2" of the well in my Oly plate.

IDEA-You could also check with someone like Zabars in NYC or here on the site to see if anyone kept a burned out element. They might even give you an old one. And then modify it...... I learned the trick from Home Espresso Repair- but I think others have been as resourceful when the supply of parts was interrupted for a while.

[TUS172]

IDEA-You could also check with someone like Zabars in NYC or here on the site to see if anyone kept a burned out element. They might even give you an old one. And then modify it...... I learned the trick from Home Espresso Repair- but I think others have been as resourceful when the supply of parts was interrupted for a while.

Great idea Greg... Is there anyone out there that may have a burnt out Oly element that would be willing to part with it?

I will still experiment since I have the plate of stainless but having the base of a burnt out element would be great.

[TUS172]

Well I realized that not only did I not have a boiler cap for this creation but also the boiler neck nut that holds down the top cover was needed. It seems that 25M nuts are some kind of rare commodity or specialty thread. Anyway yesterday I received the 25M X 1.5 bottom tap from a tool and die works out of Texas. I had also bought a couple of M24 nuts from McMater Carr. So after work I got on the lathe (at work) bored out the nut with a boring bar and then used my nifty new tap to rethread. Then since the nut was way to thick I sliced off on third of it and even put the same type of shoulder as the one on my '86 has. Of course I will have to polish it up and chrome it.


Wow it is almost ready to make espresso!


The next project will be making the boiler cap.

[TUS172]

Well I got some more shop time last night. So I had a chance to fabricate the brass boiler cap.
So I used a band saw to this brass disk and then began the real fun here at this older Rockwell Lathe.


The rest is kind of self explanatory... First I centered the peice and began to contour the outer form and then drilled and bored the peice out for threading, then finished up the exterior.



I haven't yet polished it up to final standards but I think it looks pretty nice.

I had given thought to knurling the outside rim for easier turning but I think to start with I will soften up the 90s and see how it goes.

I'll probably stick with brass... It machines easily and I really like the look. So I'll be shipping some bar stock back to McMaster Carr in the near future.

[TUS172]

After conferring with Espressme I have realized that I need to use some type of insulator to keep from frying my fingers when attempting to touch the boiler cap or steam tap knob. So I will attempt to turn some hardwood knob coverings and handle for the lever.
Anyway tonight I had a chance to turn the brass part of the steam tap knob and the insert for the lever handle.
Again I did not have time to polish things up and I still need to take down the diameter of the rim of the steam tap knob. But a couple of more small projects are "almost" finished...

[mogogear]

You are putting all that spare time you now have with the political machines all gone to Michigan, to good use!

On the heat detail and your nice knobs- Perhaps you could turn a V-groove or two on the boiler knob - so you could put a couple of nice fat rubber o-rings in place. Like a belt pulley! They would grip well and insulate and stay in place fairly well it seems.. The steam knob would be good for just one.

Just a thought- they would not need to be glued - just stretched into place. Black and brass would pretty clean...

Sorry -Too full of suggestions sometimes...You sure are having fun on the lathe!

[TUS172]

Thanks Greg... If wood doesn't work out for the knobs and lever I will take you up on that idea...

The knob for the steam tap is pretty nice...Ya... but did you note that there was no steam tap retaining nut on the end of the stam tap... Niether did I!

It turns out that the tap that I got is missing the retaining nut for the tap shaft. I don't know how I missed that when I tore it apart but after I turned the knob for it I realized that I had not allowed for the retaining nut. Then I realized I had never taken the nut off in the first place. Anyway last night after work I redesigned the tap knob by cutting the knob stem down and then taking a peice of 1" stainless and doing a press fit over the stem with an arbor press and some JB Weld. I did have a chance to polish up the rim and stem of the knob before fitting the new stainless stem.

Now that I have spoken to our resident expert on handle and knob coverings (Thanks Richard) I will attempt to turn my own. Also since I have an issue now with the new setup because I have the tap end of the knob traveling over the steam tap body... I grooved in an o-ring that makes contact with the body and keeps the stainless from touching. It also gives a really nice glide to the turn and offers two points of support for the knob. the blue color is release agent...


The valve stem is sticking out because instead of cutting a square at the bottom of the knob I opted for a round hole. I painted the stem with release agent so the JB won't adhere to the tap but will form the square very accurately. So now it sits over night and I will see tomorrow morning if I can get things apart somewhat easily. I am not worried if the stem comes out hard because it is a bit out of alignment anyway and it would take some work to get it back to true.

Also the inner o-ring has been removed but you can see the groove for it. It forms such a great seal between the knob stem and the valve body that I am going to have to drill a 3/32 hole above the o-ring in oreder keep air pressure equalized when the tap heats up...

Still having a blast.

[TUS172]

Well the release agent worked and the tap stem came out very easily. Got the hole drilled and fit the knob so that the small hole is unseen on the bottom.

Alot needs to be done yet... I figure on doing all the polishing and fine work last... After everything gets formed put together and fitted. That way I can get to it as one operation.

[TUS172]

Well it looks as if I am going to have to fabricate the steam tap valve stem. I took all the measurements this morning. I am also going to have to buy some tooling for the lathe to get it done right. It requires tooling that has bit more intricate/delicate touch than what is currently on hand at the shop. But this type of stuff was expected and it just adds to the adventure! I will also have to tune in/tighten up, the tool post, cross feed and tail stock just a tad before endeavoring into this little venture. I am not sure if I want to stick strickly with brass... but the valve body is made out of brass so I may be forced to. I think something like stainless would really take it toll on the brass over time.

[TUS172]

I had a chance to get into the shop again last night and with the extra material and tooling I was able to make a few new tap stems for the valve body of the 'C Lever Project'

Can you tell which one is the old part? At that stage I had not yet made the cups for two of the stems. I opted to make the cups from Stainless they float on a small ball bearing in the valve stem body. I figured since I had a foot of .5625" brass shaft I may as well make some back up parts.
I have yet to get on the mill and square off the ends. Only so much time after work to 'Play'.

[espressme]

Wow!
rp

[TUS172]

With the limited availability of parts and pricy costs of those being offered and since I have went so far as to custom make other parts... ... PISTONS have come to mind... ... I am giving thought to turning a couple of pistons for the Cremina. I have some left over 1.75" brass shaft.

I learned (in the not too distant past) from other veteran authors/experts on this site, that La Pavoni Pre Milennium Europiccola seals do work on the Cremina piston. The only difference being that they are shy in height by .050" in comparison to the Cremina seals. (Cremina on the left) So since that is the only difference why not opt to custom turn a piston that will have seal channels that will exactly match the La Pavoni seals. They are much cheaper than the Cremina and the availability is not an issue at all. If I do it I will turn 3 pistons since I (will) own 3 Creminas and as I replace piston seals I will replace the pistons on the others.
Things are progessing slowly and I am still having a BLAST...

[TUS172]

Well another night at the shop and another piece turned. I went ahead and turned one piston for the custom machine since the shaft I have only had enough for two pistons. Besides when I got home my wife accused me of seeing another woman... and the dog didn't recognize me... I guess I had better let up for a while.

[TUS172]

I did have a chance last night to thread the new piston (7/16 x 20).

I saved a tenth of an inch on the piston's hieght by narrowing the channels (.050" for each channel) to accept the La Pavoni seals.

I will make up the difference in the length of the stainless shaft so that the face of the piston ends up where it should at the bottom of the grouphead shaft. My thought is that the additional 10th of an inch above the filter basket when the piston is at the top of the pull it will give me additional hot water in the chamber that is formed above the puck. (Just an experiment) I have ordered the 12mm stainless shaft from McMaster Carr... I will be turning the threads on it when I get it in (7/16 X 20).

[mogogear]

Go Bob Go! Go Bob Go-- is there nothing you can't do?!

[mandioca]

Hi,
is 7/16 x 20 the original threading for this or was the original a metric thread? If you chose this, what was your reasoning for it? I am just curious.
thanks,
Tom

[starry]

Bob, I haven't had a chance to keep up with the goings-on here for a while, so I apologize for having to rewind a bit and ask you about the bottoming tap. In my PID'ing of the Cremina, I went through the same need for threads and ended up making a boring bar to turn the threads inside my little extending coupler. I also turned threads on a short nipple. I still have the 24mm nut I bought from McMaster - a mistake because I thought the threads "had to be" something standard. Dumb. Anyway, that tap you bought must amount to about half of your total cost! I'm surprized you actually found one! Would you consider renting it?? I'd still like to enlarge the threads in the nut and make the same parts you did.

[TUS172]

Hi,
is 7/16 x 20 the original threading for this or was the original a metric thread? If you chose this, what was your reasoning for it? I am just curious.
thanks,
Tom

I figured that wherever possible I would go US standard for future reference and/or replacement. I have 7/16 X20 taps and dies on hand... but I still had to buy the 12mm stainless shaft for the piston shaft so that the seal would conform properly. To keep buying Metric or BSPP gets awfully tiresome. For the boiler cap and retaining nut I had to match the existing threads. Also I had to match the lever for the fork and steam tap valve stem in metric. But as I am l fabricating other parts I go for the US standard threads.

I am spending a bundle on this project, but hey... its winter and I would just get "cabin fever" otherwise... I am keeping track of the hours and $ spent... Its a good thing this is so much fun...

I figured that once I get all the intricate parts and fitting done then I will put it together for functionality and then various parts will go out for 'sprucing up' and then the sheet metal work and polishing will be the last things I do... That may be well into the summer... I have no idea.

[TUS172]

Bob, I haven't had a chance to keep up with the goings-on here for a while, so I apologize for having to rewind a bit and ask you about the bottoming tap. In my PID'ing of the Cremina, I went through the same need for threads and ended up making a boring bar to turn the threads inside my little extending coupler. I also turned threads on a short nipple. I still have the 24mm nut I bought from McMaster - a mistake because I thought the threads "had to be" something standard. Dumb. Anyway, that tap you bought must amount to about half of your total cost! I'm surprized you actually found one! Would you consider renting it?? I'd still like to enlarge the threads in the nut and make the same parts you did.

Ya it confounded me that they would use 25mm X1.5 for the boiler cap... I mean that is most commonly used for conduit pipe in Europe... Go figure... But who am I to question. I ended up getting the tap on Ebay for around $25.00 with shipping. A tool and die shop had a couple up for bid and I jumped on one. http://stores.ebay.com/Deer-Park-Tool-Grinding-LLC
The only reason I began with a 24mm nut (bored it and then rethreaded it) was to see if I could do it easily... As it turns out I ended up having to split the nut because it was so thick... So easy? Not. If you keep your eyes on Ebay you should see one come up every once in a while.