2 Group Gaggia Tell Restoration - Page 13

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
OldNuc

#121: Post by OldNuc » Oct 21, 2019, 9:17 am

If your college machine shop has a bead blater use that to cleanup the flanges and studs. The glass beads will not damage metal oreven old cloth insulation.

I have 24+ hours on the Kynetx Food Grade Grease at 189-194F and it has held up with no bleed or sag. This perfect for the bearings and rack and pinion. Furthermore it does not stink.

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This is the condition at time zero

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This is the condition after 24+ hours and 2 heatup cool down cycles.

You can see the little peak in the grease and there is actually a bit of space under it and it has not moved.

It turns out what was originally used is a almost no longer available product sold as 600W Gear oil for use in transmissions and rear ends of 30s-early 60s cars. You can find it available from suppliers to the antique crowd. This grease will be far superior product.

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IamOiman

#122: Post by IamOiman » Oct 21, 2019, 11:15 am

Wow that is exciting news! I'll order a tub of the stuff when I get back today. I know the shop has a sand blaster but I will need to check if it also has the beads. I am in the process of ordering new stainless steel washers and bolts for various fittings along with brass nuts for some of the panelling. I did not realize how much they cost individually at places like Ace Hardware so I am ordering those multiple sized packs that come in 100-200 pieces

I have actually not seen your machine before, could you post a pic of the Orione?
-Ryan
I'll throw my portafilter in the ring
LMWDP #612

OldNuc

#123: Post by OldNuc » Oct 21, 2019, 12:27 pm

I think I can find a couple.

I find the metric nuts, bolts and, screws are much lower cost at McMaster-Carr

OldNuc

#124: Post by OldNuc » Oct 21, 2019, 8:50 pm

These are the best of the lot. Right now the machine is sitting on a 4' plastic table with a piece of 3/4" plywood preventing collapse while i get a kitchen island built.

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Operator's side

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Customer side

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Under drip tray original wiring and gas parts. gas never used

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This is the short boiler that holds about 3 1/2L

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Original seller tag

These are the as received pix and the boiler has been insulated so it holds rated pressure running on the 400w @200v element with a 50% duty cycle on/off. The insulation is incredibly expensive but also has a very high R value and is only 5mm thick. This brand product: https://www.aerogel.com/ I used the Spaceloft and I would suggest going for the more dense higher temperature offerings. This Spaceloft sheds silicone particles and is less than fun to install. The more dense material is easier to work with. Easiest place to find this in bulk is eBay

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IamOiman

#125: Post by IamOiman » Oct 21, 2019, 9:34 pm

Wow 3.5 liters is excellent for home use. I can totally see the insulation working with 400W. Pretty cool stuff right there.

I got my package of shims and gaskets for the groups and began assembling the first group. Here is the stack laid out, where the bottom of the stack is the bottom right row and goes up from right to left and up along with the resulting stack. A shim is used between brass-brass contact. For the medium shim with the three holes it will not matter if the hole is not aligned with the group inlet hole as it is concave in shape, meaning water will enter it regardless of orientation of the piston and the shim.

An interesting thing I noted is the height difference between my original top shim and the old new stock shim is such that you could remove one brass v-ring and gasket in your stack, so you have two v-rings and gaskets below and one v-ring and gasket above.
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When inserting the piston some lubricant is required to slip the piston throught the gaskets. I found the easiest way was pushing the piston from the top towards the bottom and adjust until the piston is flush with the sleeve. I also saw that the piston depth happen to be just where the top brass shim would begin if you rest the piston flush with the sleeve on the bottom.
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Now as I wait for the cam grease to arrive, I am trying to figure out how I would compress the spring without moving the piston from its initial position after tightening the large 80mm nut. If I look at it right I would need to start compressing the spring with the top part of the group not screwed into the hex nut initially and only do it when I reach it after compressing the spring part way.
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Finally I was able to snag the IMS 200 shower screens and gaskets for the back up group setup if (and probably indubitably) I get sick of the original shower screens.
-Ryan
I'll throw my portafilter in the ring
LMWDP #612

OldNuc

#126: Post by OldNuc » Oct 22, 2019, 9:32 am

I would install the packed ball bearings and then compress the spring to something close to the normal full down location.

Before that run the stack compression nut, the lower one, to just contact the tip spacer then grease the 4 seals to a nice shine with DC-111 but no gobs.

Then insert the top works into the group. Assemble and tweak so it works.

I would consider using single shielded bearings to keep most of the grease out of the cavity between the outer cover and outside of the bearing. With modern lubes you can inspect the rack on every pull and this is the high wear part, the bearings will be fine with a initial pack for a very long time.

Without the spaceloft insulation I could not heat to pressure with the 440w actual input. Now to get the steam volume to close the vacuum breaker I startup on both elements, until I get pressure and then switch to the low watt only. There is no significant change in total heatup to hot operating using the low power element only.

Those light buff panels and parts are not painted, they are actually hard fired porcelain enamel on rather hefty steel sheets. Very minor chips that can be patched once cleaned.

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IamOiman

#127: Post by IamOiman » Oct 23, 2019, 4:07 pm

It was just a matter of screwing the spring compressor to have the top of the group reach the nut. Before that I tightened the large nut by holding it in a vice while I turned the bottom group until I felt fair resistance. The top gasket will also squish a bit inwards when you do this as well.

I slathered on the grease that OldNuc tested with (I cleaned up the rack after the pic to something more appropriate) on the cam and a little in the shaft of the group top/bearing area.

Once the top group touched the nut I could turn the top group with the spring compressor, where I would tighten the spring then tighten the group top. Eventually when I had enough threads I aligned the teeth of the rack with the group top and I could put in the bearings and cam. Note if your cam has a few worn teeth (not necessarily chipped/broken) you can adjust the cam such that those teeth will not be used as the cam will not turn 360 degrees when you pull the lever, more like 180 degrees.

The group itself is not flawless, but it is better than when I originally received it. There are a few scratches here and there but I will just use a light cleaning/polishing compound like autosol. I am personally pretty happy with it and can't wait to assemble the other group once my missing bearings arrive (two of them fell out of the battered box that held my other group parts).

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-Ryan
I'll throw my portafilter in the ring
LMWDP #612

OldNuc

#128: Post by OldNuc » Oct 23, 2019, 6:33 pm

Looks great to me. There are automotive chrome polishes as the auto parts store that will work wonders on some of those light blemishes.

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IamOiman

#129: Post by IamOiman » Oct 29, 2019, 9:34 pm

I've been cleaning up the flanges on the group and the boiler face. I first used a small chisel to scrape as much gasket as I could, then switched to a brass brush and scrubbed the flanges. Finally I took a flat razor blade and scraped off remaining gasket. It is not immaculate to look at but it is getting quite flush at this time. Most of the remaining black stuff is that same black coating seen inside the boiler that tends to accumulate over time.
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One small issue I've been having is disassembling a steam wand valve. It is awkward to hold in a vice to where I can leverage a wrench to unscrew it, and the size is something odd between 25mm and one inch (25.4mm), so there is no perfect fit. How should I approach this?
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-Ryan
I'll throw my portafilter in the ring
LMWDP #612

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Paul_Pratt

#130: Post by Paul_Pratt » Oct 29, 2019, 10:13 pm

For the steam valve use 2 adjustable wrenches. I do not own a bench vice and get by with 2 adjustables. You can manouver them to form a pincer like motion. Works a treat and should leave no marks.

I do the groups a bit differently. I install the lower group onto the boiler. Then I build the entire top half, the large middle hex nut is screwed down but is not compressing the gasket stack. Then I insert the top section of the group down through the gaskets, and tighten accordingly.

Getting the piston through the gasket stack may be troublesome so I made a seal spreader. It was just an old tamper with a handle and I made it with sloped sides. The idea is the upside down tamper goes through the seals closely followed by the piston assembly. It opens the seals allowing the piston to slide through.

The gaggia group is a thing of beauty, but the upgraded dispersion screen is the icing on the cake.