I asked a local springs manufacture here in Syracuse, and as I suspected they told me it's very expansive to make 1 or 2 springs custom made. They sent me to the web page of Lee Spring, and I found this:

https://www.leespring.com/compression-s ... ch=LHC162R

LHC 162R 04S

It looks very much similar to the Zacconi spring except it's a little bit wider and seems so has a greater rate.

If I will solve the heating element issue, this might be my next quest.

except it's a little bit wider and seems so has a greater rate. This spring is very similar to the new one I have, but the wire diameter is closer to the old one at around 4 mm. Outside Dia at 1.46 is 37 mm which is the same as I measure on the new spring. Free length at 3" is 1/16" longer. At 62 lb/inch RATE, I don't think it is really strong enough though. Not so sure, but I just pressed on the new spring I have using a scale. No way I compressed it 1 inch, but used 81 lbs of force. So this one might be too weak? My old spring is in the machine right now. I didn't take 2 weeks off. Fired up when I woke and tried a 12 gm shot. The first one of the day seems to taste better, so I'm thinking as the head gets hot it's affecting the taste a lot. I pulled out a multimeter I have and saw it has a Temp setting, so scrounged around for the thermocouple wire that must have come with it. Well it was indeed in the bucket I keep some electrical stuff in. Have taped it to the side of the group head and will look at temps some. Just two shots so far today as I'm out of roasted beans. Will roast some later with the StirCrazy popcorn popper method. I might go get some Pete's beans again and try those to have some sort of comparison. The taste seemed ok from some Italian Roast ground Peet's (recent date) I first bought and then re-ground in a blade mill and sifted to a consistent small size. Might hit up some other local shops and see if their espresso is delicious. If so, could buy those beans to try for comparison. I have the 1zpresso JX-Pro hand grinder right now, and it does a very good job, but I'm grinding no where near the low setting they say to use for espresso @ 1.3 turns, I'm up around 2.5-2.6. Hmmm. Hope your thread issue can be resolved!

If you search the forums here, some of us have experimenting with installing a smaller spring inside the larger one to add pressure. You might search "double spring."

I read about it here:
Ponte Vecchio supplementary springs

drgary wrote:some of us have experimenting with installing a smaller spring inside the larger one to add pressure.

Look forward to reading about this.. was just thinking 8 or 9 bar is ~120 psi. That spring info showed a RATE of 62 pounds.. but that is weight to compress the spring one inch. The pounds per square inch applied would be different.. I guess based on area of the piston...? Can be complex to think about! The double spring seems interesting.

nirdvorai wrote:I read about it here:

I just read the first two posts in that thread. The commenter in the second post said: "One last question (a more general one to all HB's since I lack experience in these things). If one needs to struggle to tame a roast, what is the ultimate benefit of using it?" Its a very good point. I finished the Costa Rican beans I had self roasted but had the urge for cap in the late afternoon. Decided to get some Peet's beans from the grocery store two blocks away. Major Dickasons blend was the only whole bean they had and it happened to be roasted fairly recently compared to others on the shelf. Easy, quick and it gets very good reviews.. Must be ok to compare to I'm thinking. Well did a similar dose (12gm) and grind to what I've done recently and it tasted fairly good. Nothing shockingly bad like I've had several of. When I made in to a cappuccino it really was enjoyable.. Easy and good is not a bad thing I'm thinking. Would be fun if one could round up locals for something like a espresso machine pot luck. A group of people bringing different machines and coffees to see, taste and talk. I'm not in a metro area with a lot of people, but that sure would be enjoyable if it could be organized.

Edit 11:14 PST: My first shot today was terrible! haha.. What's new? Now I've realized how important temperature is. The only possibility was that things were too cold, so I heated up the head a bit more before the second shot and yup heating it up worked and the second shot much better. Gosh now will have to read more about temp control. I had moved that little thermocouple from yesterday to a new spot, so that was part of the problem. So many variables for my old brain. Better start keeping a spread sheet of shot data!

So I decided to increase the pressure in my boiler from cycling at .8 - 1 bar to 1 - 1.2 bar. Began thinking the low pressure might be a reason I wasn't getting good micro-foam, and I couldn't remember the reason I decided to drop it down to 0.8 bar anyway. One problem was I had never overhauled the relief valve and it was definitely beginning to lift around 1.2 bar. So off to Harbor Freight to get a metric combination wrench set as the one I have (and many other sets seem to leave out a few sizes). 18mm is needed. The relief valve was indeed dirty inside and seems my cleaning it up and taking steel wool to the inside cleared up the seating surface. My relief valve doesn't have any screw adjustment inside so it's just spring pressure. When back together it's not lifting early at 1.2 bar anyway, so that's great. When one has the relief valve out can get a light source inside and was able to take a few photos. Inside looks pretty good I'd say for a 50 (??) year old machine. Scraped off a little scale down on the bottom near the water inlet hole. Steam frothing is definitely a little better at >1.1 bar than before at the lower pressure. Seeing a tiny bit of progress with Latte Art. Now I'm thinking why not go up a little higher with the pressure even?

Wayne and others, on boiler pressure, brew temperature and microfoam, I've found that the sweet spot varies between machines. I think a La Pavoni home lever runs relatively low, at about 0.8 bar for later versions. I believe I ran my Elektra Microcasa a Leva spring lever at about 1.1 bar. To tune your Riviera, you'll want boiler pressure low enough that you can use a heating flush to increase group temperature and not so low that you can't do steaming comfortably. And then there are things you can do to vary brew temperature to suit a particular coffee, like doing heat flushes. You can dial in temperature by measuring it on the outside of the group and correlating that with the taste of the coffee to make a good guess about brew temperature. Temperature strips are an easy, non-destructive way to read outside group temperature, or you can get a thermometer you can attach to the outside of the group. To find the best temperature for a particular coffee for this exercise, I like to brew it with a controllable immersion method, like an AeroPress, French press or Clever Dripper. Doing this helps you find the offset between the temperature you measure on the outside of the group and the target brew temperature.

drgary wrote:To find the best temperature for a particular coffee for this exercise, I like to brew it with a controllable inversion method, like an AeroPress, French press or Clever Dripper. Doing this helps you find the offset between the temperature you measure on the outside of the group and the target brew temperature.

Could you give more details here? I'm not getting what you are using for those brew methods to temp on the group head.. All this temperature stuff gets me thinking I might like moving to a more sophisticated machine at some point. Have you seen the Lelit Mara X and Technika Profi? Pretty fancy machines, but sure would be nice!

drgary wrote:To tune your Riviera, you'll want boiler pressure low enough that you can use a heating flush to increase group temperature and not so low that you can't do steaming comfortably. And then there are things you can do to vary brew temperature to suit a particular coffee, like doing heat flushes. You can dial in temperature by measuring it on the outside of the group and correlating that with the taste of the coffee to make a good guess about brew temperature. Temperature strips are an easy, non-destructive way to read outside group temperature, or you can get a thermometer you can attach to the outside of the group.

I've got the cheap multimeter thermocouple taped on. Seems pretty accurate though as it nailed 100c for boiling water first time. I do like it for the temp information and am starting to keep a spreadsheet of data for the shots. But wondering, if temp needs to be controlled by flushes and/or cooling anyway, why not just run at the higher pressures? Is the water just too hot at say like 1.4 bar? (1.0 bar = 249 f, 1.4 bar = 259 f ???) For pre-infusion I suppose are we expecting the water temp to be cooled by the group and to what temperature for that water? The shot water hangs out in the cylinder for a while so I guess that is cooling there too. Makes me think we don't want our group all that hot at the start of a shot.. ??? Have you ever measured the temp on the outside of a machine like these prior to a shot? What do you imagine a good temp would be given the mass of the brass head? Thanks for your messages and help here!

I'm suggesting a way to get to know what temperature your home lever is achieving inside the group so that you can achieve consistent temperature control of your shots. I'm not suggesting you need a better machine or a spreadsheet.

Measuring temperature outside the group with a probe works well. If I'm dialing in a home lever machine, I like to guess the offset between the temperature on the outside of the group and the temperature in the brew chamber. These days I do it by taste, but if you're just learning, you might start with a coffee you know well and brew it at a temperature that works for that coffee. I like an "immersion" method (not "inversion," sorry, my mistake) because it gives a very good idea of start temperature. I measure the temperature of the water in the kettle just before I pour it in.

Here's an example. Let's say I have a nicely developed medium roast that brews well in an AeroPress at 202°F/94°C. The AeroPress is a plastic cylinder that's a good insulator and it seals off well, so the temperature won't drop much. Other immersion methods like French press or Clever Dripper work well too.

I would like to pull an espresso shot with that same coffee. You know the taste you're aiming for because you've dialed it in using your AeroPress. If you brew it too hot it will taste burnt. If you pull it too cool it will taste sour or otherwise underextracted. When you get the temperature right, note the temperature you've measured outside the group of the lever machine at the start of the shot. Let's say it tastes right when the temperature on the surface of the group reads 195°F/91°C. That means you have an offset at the start of the shot of -7°F/-3°C, because this coffee tastes the same at 202°F/94°C.

Home levers can easily overheat. You can cool the group in various ways, but if you avoid overshooting, it's easier to pull back-to-back shots. For this reason, I like to have the group start a little cooler than the target temperature. This is achieved by setting boiler pressure/temperature so it's cruising a bit low when the machine is warmed up, so that methods that bring the group up to temperature give you good control. A heating flush or a half pump sets your group at a desired start temperature. (A half pump is when you partially cock the spring to let water into the top of the group, not the brew chamber, and then return the lever to starting position, uncocking the spring.) Another advantage of avoiding overheating the group is that you can surf to the right temperature for different coffees in the same brew session. Clear as mud?