Hello.
The machining is actually not done by me specifically but with a company that has helped me from the beginning and has Machined all the models so far.

Your probably right that the 4 axis rotational headstock is probably stiff enough to hold that component. But I think it's there to help with rigidity. The jig that holds the component is steel and quite solid. So it may deflect very small amounts which we don't want as there are
Many precise cuts for seals, valves and orings etc. So yes it is engauged in the Jig to answer the question.

Thanks for the interest

I actually tested the new bottom housing today using some 3d printed parts for the top housing as they are not fully machined yet. The machine is far hotter than the last design. So much so that I can barely touch it after one flush. In fact it seems so hot without a flush. The coffee was a lot better to. The smaller housing combined with deeper pockets has made an incredible difference. There is far less mass to heat and the hot water is inside the housing. The coffee machine is definitely up to temp very quickly. I think it will be a very useful machine once people work out how they choose to manage flushing according to their own requirements.

Don't take these photos to seriously but this shows I have tested the new parts. All the rest of the parts will be completed soon finished and annodised so I can do. Some have said here I should just post more photos and not to be so fussy as you are most interested in how things are going. So I hope this approach helps communicate progress better

I'm keen to do some proper shot testing and provide those specific videos and shot profiles some have asked for and when the parts for the complete machine arrive I will get into that.

Note in the photo a lot of things are just for testing. Gauge has not been tapped to the right depth etc. I just wanted to simply test operation before continuing machining the rest

Looking good

Hi

Woodwork all complete. 3 coats of epoxy sprayed as well as a sanding sealer coat. Same coatings and company that does internal Timbers for the likes of marine kitchen finishes.


The wooden coatings are hard and should last a lifetime. Highest of quality finishes done by hand. Polished brass fittings and stainless cylinder rods and legs will also compliment the wood and glass. No expense spared with the finish which has been a focus. This high quality finish will look great in any high end environment, perhaps a nice talking point in your lovely bespoke kitchen!

TheGriz wrote:I love the design and everything. Reminds me of my Portaspresso Rossa; I absolutely love the coffee from that. I have two issues though that would prevent me from purchasing: temperature and pressure profiling.

With everything you have built, you should be able to pressure profile. Long slow preinfusion and a decreasing pressure while pulling to maintain a constant flow rate. I drink light roasts and this is pretty much required to do to get a nice syrupy, flavorful espresso. You should showcase this feature. For me, this is one of single most important things about lever machines. Prove that you can pull off these with very fine ground espresso and people will be more interested.

The profiles I usually use for light roasts:

• 10-20 seconds of water just touching the puck
  10-15 of preinfusion of 2-3 bar until beading
  40-50 second pull with a profile of 8-9 bar until proper flow with constant decreasing pressure down to 4-5 bar for the length of the pull.

I aim for 16-18g coffee in and 2.25 times water volume out.

The second aspect being temperature is a universal element. Different roast levels and origins require different brew temperature. You need to be able to prove that you can get the temperature above the puck between that 195F and 205F. Those are the minimum requirements since those are the agreed upon standard for coffee. That's what it takes to dissolve those coffee solids and get the proper extraction. Check the temperature of the coffee output compared to a standard machine you own as well.

I would also invest in a TDS meter of your choosing and post those results. Most individuals look for the 20-21% extraction. Some prefer higher or lower than those numbers, but you want to achieve around this. SCAA has the optimum range from 18-22% for reference. SCAA numbers are for your benefit. Plus it provides a standardization that you can wear as a Medal of Honor.

Once you can prove your machine can accomplish these feats, you will sell more machines. Your machine is designed for coffee enthusiasts and these are some of the standards we look for. Hope this helps.

Hi again,

As you mentioned a while ago you would just like to see more video content no matter what the quality, showing as much as I can on the journey.

Well I picked up one of the raw machined new bottom heads not annodised yet and fitted the valves and glass tank and piston and pressure chamber. I connected the new fitted bottom head to a 3d printed exact version of the top head fitted with the winder shaft and pushed some shots out. The new bottom head is absolutely epic. I had my 14 year old teen hold the I phone for Video. Forgive me for the home grown video ad -hoc environment. Maybe you might like it I hope!!.

I have no concerns about the heat of the shot. Its seems very hot the instant you fill it with boiling water and vastly changed in terms of the shot from the machine, the coffee is definieltly darker in colour. I hardly think I need to flush at all but I flushed once anyway using the normal technique. The coffee was no different to my commercial plumbed La Cimbali junior, in fact better thicker coffee to be honest. The roast was one of my normal blends designed to be used to cut milk and pull nice espresso so not exactly what you wanted to see in terms of light roasted. Anyway after 1 min and a flush I can pull a shot from cold in about 2 mins. The updated machine design on the bottom head is very hollowed out and a fill of boiling water is now virtually sitting only 2.5mm above the portafilter seal and basket. So it gets to temp fast. Also the glass tank is quite large at 90mm diameter so it has a good potential of energy stored and after one flush maintains that head excellently. The flush is very easily performed from the front using the tap into your cup. No messing around emptying hot water by hand. The tap location is low holding all the boiling water internally in the machine, and the tap flushes fast!! with good flow. Emptying takes no time at all.

Anyway I tryed to understand your desired shot pull as below;

10-20 seconds of wateCr just touching the puck
10-15 of preinfusion of 2-3 bar until beading
40-50 second pull with a profile of 8-9 bar until proper flow with constant decreasing pressure down to 4-5 bar for the length of the pull.
[/list]I aim for 16-18g coffee in and 2.25 times water volume out.

I would have to say that unless you have a very good grinder after holding 2-3 bar for over 35 seconds (the water on the puck followed by the 2 bar preinfusion time you listed above ) its going to be almost against the rules of espresso to expect the puck to resist and hold another 40 to 50 seconds at 8 bar. The wetness and length of time of that water on the puck will just wear the grinds down and the pucks potential to resist and generate that force for that length of time after that in my experience is asking alot. I just dont see many other than perfect setup achieving this. There is no way to do this on an electric. And I think this profile is definitely far out of the ordinary pull. But anyway its cool you like to try something different and who says any technique is correct, its what you like to drink. So I need to have the folk here recognise that this is not easily achieved and quite a long way out of the norm of how most will make espresso on my machine. Most will try for a 35 second pull achieving 9 bar and ramping off to lower pressure perhaps for their normal daily espresso routine which Expression can do so easily its childs play. But with a very good grinder and some time as you can see you can do virtually what you want with time and pressure by just vary the speed at which you wind with the tamp and grind setting.

Nervertheless I tryed for you to show the control of pressure for what you want to do and I would say that the shot reflects what im saying about espresso in general. The coffee does not resist the puck after the long preinfusion for that long and gets quite thin in the pull and even thinner later on. But I did not roast specifically for this nor grind anything finer than what I would do for a normal daily espresso on the La Cimbali and also the basket is only a 14 Gram. It looks like you use a 18 gram plus dose as listed above. Expression comes with a 14 gram laser cut ridgeless double shot basket. So I could achieve closer to what you wanted with a specific roast, grind and dose. However I do thank you for sharing this type of preparation because its cool to see what others do.

The new machine in general is easy to turn at pressure, holds your pressure point quite well and is controlled by speed of rotation. It is not hard to turn the handle at all holding 8 to 10 bar. In fact significantly less force is required for the same pressure than any other non spring lever pull as Eric Mann touched on when he tryed it. Its pleasant to use

I hope you enjoy the video. Sorry for the quality of the video and having to use the plastic top head, new ones almost complete and should be ready in less than a month now all finished and packed. I hope I havent shot myself in the foot posting low quality videos not showing the full finished version of the machine and using testing parts but I trust your comment that folk here are most interested in whatever I can demonstrate. Know that the full finished polished versions of the machine will really impress in terms of the finish
Also I have some more photos of some of the parts made yesterday. The top handles and distribution disks

Hi again,

Today we did another video with Expression. This is obviously another pre-testing model we are using for making shots. It is no reflection of what the machines will actually appear like in terms of finish. The finished machines are in the final stages of production and its coming along very well

This time we made a video showing the speed of draining and flushing and reloading fresh hot water. Then making two shots in a row, one using a slower pre-infusion and one slightly quicker. The basket was a 18 to 20 gram.

I hope you find the video interesting in terms of showing how fast it is to make multiple shots of high quality without power. As you can see I could carry on and keep making shots, one tank does about 4 shots so its very fast in terms of knocking out multiple coffees for your friends.
Also a photo of the boxes that have arrived for packaging with Expression logo burnt into wood.

Very interesting.

I applaud all the effort that has gone into this very cool project.

Thank you. Looking forward to showing you the latest finished completed machines lined up. And also pulling some shots for more videos on the real ones. !!

Hi,

Most of the machining is done, Pistons, and brass tap fittings and knobs, portafilters, drip trays, plus top and bottom housings. Off to annodising and the brass off to polishers. I think we are only a few weeks away from assembling these machines.

Notice this piston is one piece and runs a wide groove quality lip seal, far more effective than orings which are commonly used and cheaper but not good under high pressure



Dispersion disk



Screen holder and second part to dispersion disk



Two parts of dispersion disk and screen holder in place


Taper brass male tap detail prior to polishing


knob to hold on winder handle


Tap handles


Piston position indicators


Drip trays


So quite a bit done now and testing of machine with recent videos very successful. Excellent espresso produced in no time at all.

Hi
Here is something quite interesting.

New head and old head weight. Quite a difference. Also the new head has hot water internally right above portafilter. Older one the heat Has a lot of alloy separating the portafilter

New head design


Older head



The two heads built up side by side. You can see the difference in design. Tap position lower. New head hollowed out for heat efficiency of
Shot and lower tap position holds hot water inside machine right by portafilter