I have a lot to learn about why I am doing this lol. Will give a lot more data soon.

That Clippard Pneumatic needle valve is rated for less than 7 bar. That's going to fail, possibly dangerously.
https://www.clippard.com/part/GNV-5K

How is 300psi max inlet pressure

1. "7 bar"?
2. "Going to fail"?

The 100psi air "rating" is a "we guarantee that this valve will follow the designed flow curve to +/- x% when used with air @ 100psig" type of a rating. Clippard makes good stuff.

Nice work Eric!

- Jake

JRising wrote:That Clippard Pneumatic needle valve is rated for less than 7 bar. That's going to fail, possibly dangerously.
https://www.clippard.com/part/GNV-5K

I appreciate you looking out for me. I believe it is rated as Jake says though, and the valve isn't going anywhere, its a solid piece of metal.

Here is a shot of the machine being used with the needle valve. The beginning of the shot is set at 1/4 turn during the preinfusion. I then turn the paddle full open to achieve 9 bar, and then you can see how precise control I have of the pressure with the needle valve. I go from 8 bar, to 6, to 5 bar and it holds steady there.
This is more of a demonstration than anything. The shot was not incredible, but it wasn't bad.

Perfect demo! Beautifully well done, mate.

Now that you've done it and had your first so-so shot, you have realized your first step on the road ahead of you. Which is that not all coffees all the time benefit from this capability. Depending on your taste in coffee and the capability of your grinder (didn't read your bio so I don't know what grinder you have), you might not even need to profile your shots. Although most can benefit at least from tailing off the flow rate a little in the final third, where the puck erodes and the flow tries to increase.

Now give the first seven post here a read. All of it is fully applicable to your machine: Lelit Bianca Review Just the first seven. I still go back and read over it every so often.

-Peter

So because I had already ordered the other valve, I decided to try the machine out with it as well. This required quite a few unique fittings to allow for the use of copper lines, but with some brazing, I was able to make the 1/4 to 1/8 compression work.

The needle is definitely different in terms of how it acts, but it is really just as easy as using the larger valve, with only 1/4 more revolution being played with. I like how small it is, and the hole to drill into the face plate would only be about 1/4" instead of half an inch, so if the mod were to be reversed, the hole could be plugged with a small screw.