1958 La Cimbali Gran Luce Automatica (Hydraulic) [Finished] - Page 6

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IamOiman (original poster)
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#51: Post by IamOiman (original poster) »

Polishing Stainless Steel

I've been meaning to try polishing stainless steel for a while, and my first opportunity arose with the Gran Luce. One of the two hydraulic caps that houses the big piston seals is stainless, checked with my metal guy, and I decided to try and see what happens if I polish it myself.

There are two steps for polishing stainless with a buffing machine. The first step is a sisal wheel with black tripoli. I purchased very large (for me at least) 8" diameter wheels for this task, double stacked. Each wheel is 0.75" in thickness, so I have 1.5" of polishing surface I can do at a time. The surface speed is a decent chunk faster than my 6" wheels. Sisal is pretty aggressive compared to spiral wheels, and I had to run the wheels without polishing for a few minutes to allow loose rope to fly off. I wheel raked them too before applying the black tripoli. Finally, I had to take off my protective cover on the sisal wheel side due to the large diameter.

I was very surprised at how firm sisal is compared to spiral cotton wheels. I could press pretty aggressively against the wheels with the workpiece, but I had to maintain serious concentration with the big diameter wheels. While polishing I was almost cuddling the workpiece like a football (but with a hand on each end) to make sure it did not go flying. However, the results were almost immediate. Just a firm pass on the steel was all that was necessary to wipe away grime and small scratches.

Once I wiped away the black tripoli compound, I went over to my spiral wheel. I only had one clean 6" wheel on me so that is what I used for this second step. I used green compound, which I am told brings out the luster in stainless. That is pretty accurate. It was incredible how much more luster appeared with the green tripoli, and I only spent maybe 5 minutes total between the sisal and spiral wheels polishing. Only one cap could be polished this way since the other one is plated copper, but this was a good first piece to try out.



-Ryan
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RTM
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#52: Post by RTM »

Nice polish work! I use a similar Baldor buffer. I really suggest some old pillows or foam on the floor to catch the inevitable flying part. I usually buff in welding gloves because the parts get so hot.. :mrgreen:

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IamOiman (original poster)
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#53: Post by IamOiman (original poster) »

Chassis Assembly

Waiting for the lids and flange mounts, I cobbled together the rest of the frame chassis with the boiler. The frame base has four screw holes for securing the boiler, with the threads being located inside the four 'feet' of the aluminum K frames. There are four actual chromed feet that thread directly in the frame base too. They were simply cleaned up and kept as is. New #10 stainless screws were used. I was able to clean up the originals, but I wanted to be sure no rust would occur. I also applied nickel antiseize on all fasteners threading into aluminum for extra precaution.




There are six frame pieces that attach to the K frames (one of them, for the front/drip tray not yet installed here). Original fasteners are used where I can, but I have replacements if I deem any unsuitable for use even after trying to clean and repair them. Until I receive my boiler lids and the gas shield I cannot really proceed with assembly.


-Ryan
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ira
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#54: Post by ira »

Pretty impressive. I might suggest that anti-seize is inexpensive and I would personally never use that little as I don't want to miss a spot and regret it years later when I go to take it apart.

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IamOiman (original poster)
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#55: Post by IamOiman (original poster) »

The pic was just for demonstration purposes; the actual amount of anti seize used was more than this :wink:
-Ryan
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#56: Post by RTM »

ira wrote:Pretty impressive. I might suggest that anti-seize is inexpensive and I would personally never use that little as I don't want to miss a spot and regret it years later when I go to take it apart.
antisieze can be a dab will do ya glob will screw ya kind of deal :lol:

ira
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#57: Post by ira »

Not when it's only there for corrosion protection, at least not in my experience. Certainly in an espresso machine you want enough to get between the head and what it's attaching. What problems does to much cause other than making a mess?

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#58: Post by austinado16 »

I'm really enjoying seeing the progress. Great work!!

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#59: Post by RTM »

ira wrote:Not when it's only there for corrosion protection, at least not in my experience. Certainly in an espresso machine you want enough to get between the head and what it's attaching. What problems does to much cause other than making a mess?
Thats the only problem( here), it does not take much extra to go from just enough to all over your hands and workshop :wink:

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IamOiman (original poster)
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#60: Post by IamOiman (original poster) »

I'll note I was able to keep my hands and work surface clean during application of the anti seize and install 8)

Group layout

I am getting ready for assembling the groups, which will be done in two parts. Note in these pics the group flange is missing along with an aluminum ring and its six bolts. The lower groups will be installed first, and I will assemble the upper assembly (big piston housing + valve block) when I test seal the group valve blocks with my flojet that operates at around 2.7 bar. The number of seals on each group is ridiculous. I counted at least 45 gaskets per group, and I need at least one more with packing cord on top of that. Over half of these gaskets live in that valve block, which is why I want to make sure it seals before install so I reduce the chance of issues appearing that require taking it back off.








Here are the boiler lid fasteners. I will likely need to replace a few of the originals due to how severely bent a few of them are, but I got pretty dang close to these equivalent modern square head bolts. They are 3/8 UNC threads just like the old ones (not BSW as I thought earlier), with just very slightly longer threads and a shorter head than the originals. I could even use modern 'heavy head' stainless steel nuts. Heavy nuts just have a wider and taller nut profile than normal ones, and are about identical to the original non-stainless nuts (the ones I got are 11/16" head size and 23/64" tall). I also purchased new stainless C clips that hold the bolts in place for install. The clips are not designed to fit in the square recess of the K frames (that is only for the bolts), and to fit around the boiler itself the opening needs to face towards the boiler center. They are good fit and will not rust.






At this point I needed to dig out a card table to hold all of the stuff I am getting ready to install

-Ryan
Using a spice grinder violates the Geneva Convention
LMWDP #612