I'm also using a sama lusso. Based on the portafilter design, its a very early model (early 1970s I believe). As with many home levers, the early models seem to be built more robustly than the current iterations. My spring doesn't seem to apply uneven pressure. Any time there's a flow problem, there's always a reason if I examine the puck.

FWIW, PV bought sama's (Dampa's) patents, and all the existing stock of parts. Many PV lussos have sama badged parts in them. They are the same size, and all parts are interchangeable. Modern machines are known to be built more cheaply, however.

Seacoffee wrote:Doug I have tried to find the posts on bent springs causing uneven extractions without no success, do you have any links?

Thanks John

Search the term "deformed spring" and you will find plenty of posts.

Yes cannot see much on deformed springs and uneven extraction but saw the new post you started. I agree with Peacecup, even with a deformed spring, the piston must stay relatively straight and nevertheless the water pressure must still equal anyway.

Wow, super interesting discussion! Thanks for going into much more depth to what I raised, all.

Something I've noticed when trying distribution methods like Peacecup's is that an influencing factor in the side to side beading vs even beading is in the way I pour the grounds in... if I do it linearly, rather than centrally and then shake I get a side/linear beading pattern. Let's face it, I could almost splitting hairs here but I do notice later blonding with even beading at home.