Original/old knob like in the pic posted above.
The new handle is more like a round circle/ball.

Wow, good discussion, much beyond my original intent though. Here are some more thoughts and comments:

Thanks for posting a photo of the old lever. I can see that it would be easier to grasp without getting burnt, as it is at least twice as long as the current one (looks nicer too).

This afternoon, I pulled some more shots and had to grab the little knob and shaft with a rag to adjust it when the little knob was facing away fro me. I can see that the old knob with an angled hole might be a good solution, but I don't have the facilities to drill and tap a new hole (and I don't have the old knob anyway).

Re the question about how the knob is fitted, the shaft is drilled and tapped radially (i.e., on the side). The little knob has a matching captive stud (screw), which btw is very short...just a few threads are exposed.

I still say the best solution is a flat, round, fluted, hard plastic knob of about 1 to 2" diameter that would fit right over the shaft. It could be held in place with a set screw in the existing hole without having to re-drill at an angle. Yes, it would look a bit odd, compared to the sculpted handles on the Synchronika, but it would be infinity easier to turn. It would also be more accurate to set in any given position, especially if it had a little hash mark on it. I wish I had a working 3D printer; I can't help but feel the solution, for me at least, would be child's play to produce.

Re the value of being able to turn the needle valve to its extremes, yes, I can now vouch for that being an important factor. I pulled a series of shots at various static valve positions (i.e., I did not change the setting during the pull). Wow! The difference between the shots is absolutely striking.

Nunas wrote:I still say the best solution is a flat, round, fluted, hard plastic knob of about 1 to 2" diameter that would fit right over the shaft. It could be held in place with a set screw in the existing hole without having to re-drill at an angle.

I agree. This is a better solution.

I have the original knob, but I have a smaller homemade round knob similar to the "new" design that I use now. I like the shape of the original knob better but as we know it restricts rotation. The round knob I have does allow full rotation. I think a great solution would be a combination of comments made here. Take the original elliptical knob, but make a longer metal cap that goes over the splined part of the flow control and use a set screw to attach the cap. That way the knob is high enough for full rotation.

BUT, in my observations and usage I don't need full rotation. I typically only use about 1/2 to 3/4 rotation, from full off to a flow that achieves brew. The process that has given me the best results is to have at about 1/4 -1/3 rotation so that the pressure goes up to 1 Bar and I close flow completely. This allows the puck to saturate and bloom for about 30 seconds. The puck darkens evenly across the bottom, and at about the 30 second mark the first drops fall and I slowly open the flow to about 2/3 to 3/4 watching the group pressure go up to 5-6 bar then as the shot starts flowing well and is about 3/4 of finished weight I slowly reduce flow before shutting off the brew lever. From first drops to finish in 30 seconds with a total time of 60 seconds. I have had good results with this process, but what works for me might not be someone else's cup o' (i.e. YMMV).

One thing I have seen is that full open flow with the flow control device is WAY faster than the original mushroom! It literally gushes.

BTW, excellent thread! And NO, you do NOT want to grab the metal cap. Don't ask me how I know .

Good news! I've also directed my comments to WLL. Today I heard back from the. They and Profitec/ECM understand the issue and are working on a third knob design. I'll be getting a free one, and I assume so will other previous buyers. While it is easy to be critical of this small debacle, it is great to see a company stand behind their products. Also, good to see a company that listens to their customers. My fingers are crossed that 'the third time's the charm'

I've changed the title of this tread, removing the "Burnt Fingers" bit, as I'd like to expand the scope somewhat.
Today I compared the flow of my stock Synchronika to that of the flow with the Flow Kit installed and set at different angles.

The flow of the stock machine was 150 ml in 12 seconds (12.5 ml/s).
Here's the flow at various handle angles with the Flow Kit:
0-degrees (closed) was 2.68 ml/s
90-degrees was 5.56 ml/s
180-degrees was 7.14 ml/s
360-degrees was 11.07 ml/s
540-degrees (a turn and a half) was 30 ml/s

I don't know what any of this means...it's just something I wanted to mess with . Interestingly, closed is not 'off', as there is still some flow. At one full turn from closed, the flow rate is more or less the same as the stock machine. Below 3/4 open, the curve is reasonably flat; beyond this point, it hockey-sticks.

I've not yet done any testing with a proper load of coffee in the portafilter. Although I did pull some shots at various handle angles and they are stunningly different.

Has anyone else messed about like this?

I tried starting a topic on this subject a while back, but it quickly stalled. I have yet to get back to developing a thesis statement to try and test...

By all means, if you draw any conclusions, please contribute!

Using water debit to adjust espresso brewing parameters

Cheers!

- Jake

2 1/4 turns is kind of a deal breaker for me. The poor handle design will likely get fixed, however 2 1/4 turns seems overly cumbersome.

That's interesting. Mine, recently received, turns only 1-3/4 turn lock to lock. Perhaps they've already addressed this issue.

Here's another interesting test and observations, however irrelevant
I tested my Synchronika with a blind basket. To do the test, first I flushed a couple of times to purge the air from the portafilter.
With the flow control closed, it took 12 to 17 seconds for the brew pressure gauge to reach 9-bar.
With the flow control at 90-degrees open, it took 6-seconds.
With the flow control half open it took 5-seconds.
With the flow control 3/4 open it took 3 seconds.
With the flow control 1-turn open it took 4-5 seconds.
With the flow control 1-1/2 turn open it took 2 seconds.
(fully open on mine is 1-3/4 turn, which I did not test.

This was kind of what I expected to see. Again, I don't know what use to make of this information...I'm just messing around, trying to understand the thing.

Now for the interesting bit, which I simply don't understand. At closed, 90-degrees and 1-turn, The brew pressure continued to creep up past 9-bar, stopping at 12.4 bar . On the other settings it did not rise beyond 9-bar (which is what my pump is set to). What gives?