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NS Oscar tight portafilter

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  • The_Baz
    replied
    Originally posted by hotwasabipeas View Post
    I am curious if you guys have an older Oscar. Mine is from 2006 and it came with the older style non-ergonomic portafilter. When using that one it fits perfectly into the group and locks in around 6 O'Clock. I also have a newer style NS ergonomic portafilter, the one that ships with new Oscar machines, and it locks in immediately and I cannot get it anywhere close to the 6 O'Clock position. There must be some difference in the shape and design of the newer portafilter that causes it to lock in immediately in my Oscar. Here are some pics:
    [ATTACH=CONFIG]2383[/ATTACH][ATTACH=CONFIG]2384[/ATTACH]
    I have exactly the same group handles as you and have exactly the same problem. I never had any problems getting the group handle to seal until around my third group head gasket, (Genuine NS flat)
    and then I had a lot of trouble getting a good seal. I think this is around the time that NS started to put groves in the gaskets. I even re-installed the old seal, (fortunately removed before it became brittle), to see if it was the seal causing the problem, and it sealed fine with the old seal. The only solution I have found that works, has been to get conical seals from coffee parts (700623) and machine then down to 8mm in my lathe, (I think 7- 7.5mm would be ideal). They never leak, but occasional if the dose is too much, the group handle will wind off while pulling a shot.
    Does anyone know if the genuine NS conical seals, (02280020.C, same for the Oscar, Musica, and Appia) are shallower than 9mm at the tip of the cone? I have never tried the genuine conical seals.

    Leave a comment:


  • hotwasabipeas
    replied
    I am curious if you guys have an older Oscar. Mine is from 2006 and it came with the older style non-ergonomic portafilter. When using that one it fits perfectly into the group and locks in around 6 O'Clock. I also have a newer style NS ergonomic portafilter, the one that ships with new Oscar machines, and it locks in immediately and I cannot get it anywhere close to the 6 O'Clock position. There must be some difference in the shape and design of the newer portafilter that causes it to lock in immediately in my Oscar. Here are some pics:
    Click image for larger version

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Name:	Oscar Portafilter (1).JPG
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    Leave a comment:


  • Casa Espresso
    replied
    Hi all
    The original Oscar seal is a flat, squared edged shape. When we servive the Oscars we replace them with a conical shaped NS seal that is used in the Appia. This gives the right thickness.
    There is another NS conical seal that is used an the Aurelia that is thicker and will cause a tight group handle if used. They look almost the same so it is easy to get the wrong one.
    Make sure yo use the thinner connical seal that is used in the Appia
    Cheers
    Antony

    Leave a comment:


  • lemoo
    replied
    the original NS Oscar seal is a flat one
    I had to replace mine as well when I had the oscar

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  • beersandwich
    replied
    Thanks for the reply,
    Have just replaced my seal with the conical Oscar style unit and still I am finding to filter too tight. Did you use flat or conical?

    Regards

    Leave a comment:


  • russellb
    replied
    Hi,
    Yes Stew. I replaced the group seal. Spoke to coffeeparts, who have a selection of thicknesses.
    IIRC I measured the old one and got a slightly thinner one, but they were kind enough to include a paper spacer, which just made it "right"

    Looking in old emails, it appears I got
    703407 Group Head Seal (72x58x7 mm)
    Just about time to get a new one now

    Regards

    Russell

    Leave a comment:


  • beersandwich
    replied
    Hey Russell,

    I am also having the same problem. Did you find a solution?

    Regards,

    Stew

    Leave a comment:


  • russellb
    started a topic NS Oscar tight portafilter

    NS Oscar tight portafilter

    Hi all,

    My Oscar is now about 16 months old and I am very pleased with it, fitted with anti-vac valve which works well, as I run it on a timer, otherwise original.

    After the year-end festivities with lots of visitors I have found that the portafilter has become  very tight to turn into the group head. IIRC it used to turn to almost 6 oclock position, but now I can get it to about 7 oclock only with a very heavy heave, which doesnt make for a lot of engagement of the lugs, they go in at about 8 oclock. The only change I can see may be relevant is that I have been swapping between single and double baskets because of needs/desires of visitors, but I cant see any build up of material around the filter mount, or under the filter lip and it has the same problem with either the standard handle or a bottomless portafilter. Ive tried putting a bit of food-grade grease on the lugs, without benefit.

    I thought the seal must have hardened, so replaced it, but no appreciable difference. There was no great amount of coffee residue under the seal. 

    Only effect other than worrying that Ill bend the handle or have it fall out of the group is that Im using 0.5+ gram more coffee to give a dry puck.

    Id be grateful for any thoughts about the problem.

    Regards to all

    Russell
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