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Thread: Is it wrong...

  1. #46
    Join Date
    May 2008
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    Quigley Hollow, Nuneaton
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    8,968
    Quote Originally Posted by pelletcaster View Post
    If nowadays you like to switch such an old system to a synthetic seal, easy-peasy with an adapter,
    Now I wouldn't bother with the adaptor on the leather sealed piston to convert to a synthetic seal for three good reasons.

    1) John Knibbs is knocking out synthetic sealed Pistons complete with seal at 30.

    2) The adaptor adds 27grams to an already heavy piston.

    3) The adaptor reduces the already short stroke of the leather sealed piston by another 4mm.


    Here's the three strokes and weights of the three setups :-

    Factory Synthetic sealed piston ------------- 69mm stroke - piston weight 264g

    Factory Leather sealed piston --------------- 65mm stroke - piston weight 294g

    Leather sealed piston adapted to synthetic - 61mm stroke - piston weight 321g


    Saying all that I do like to start off with the old leather sealed piston as you can machine the nose back easily to end up with a lightened piston with a 71mm stroke.




    All the best Mick
    Last edited by T 20; 13-01-2017 at 03:48 PM. Reason: Just for Arthur

  2. #47
    Join Date
    Aug 2009
    Location
    Pontypridd
    Posts
    1,807
    321g

  3. #48
    Join Date
    Mar 2014
    Location
    A-9063 MARIA SAAL
    Posts
    100
    My thanks to

    T 20 / Mick
    &
    Geezer

    for their - at least for me - valuable information.

  4. #49
    Join Date
    Mar 2014
    Location
    A-9063 MARIA SAAL
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    100
    Quote Originally Posted by vestlenning View Post
    Mine is a 1980 leather, now plastic piston seal. Nothing done to the TP but the rifle works just fine, consistent at about 220 m/s with JSB Exacts.

    http://barx.org/airguns/?id=hw_35

    Thanks
    and congrats - nice gun.

    BTW - do you have the TP-Dia dimension?

  5. #50
    Join Date
    Mar 2014
    Location
    A-9063 MARIA SAAL
    Posts
    100
    Quote Originally Posted by vestlenning View Post
    Mine is a 1980 leather, now plastic piston seal. Nothing done to the TP but the rifle works just fine, consistent at about 220 m/s with JSB Exacts.

    http://barx.org/airguns/?id=hw_35

    Thanks
    and congrats - nice gun.

    BTW - do you happen to have the TP-Dia dimension?

  6. #51
    Join Date
    Oct 2015
    Location
    Western Norway
    Posts
    163
    Quote Originally Posted by T 20 View Post
    Now I wouldn't bother with the adaptor on the leather sealed piston to convert to a synthetic seal for three good reasons.

    1) John Knibbs is knocking out synthetic Pistons complete with seal at 30.

    2) The adaptor adds 27grams to an already heavy piston.

    3) The adaptor reduces the already short stroke of the leather sealed piston by another 4mm.
    Depends. My 35 has an adapter and plastic seal and is consistent at about 220 m/s - plenty for my use.

  7. #52
    Join Date
    Nov 2001
    Location
    Blackburn, Lancs. (under a bridge)
    Posts
    19,369
    Quote Originally Posted by Robert_Lavin View Post
    ... to want a HW35?

    Rob.
    No.

    HTH
    Ian

  8. #53
    Join Date
    Apr 2002
    Location
    Bolton
    Posts
    12,249
    Quote Originally Posted by T 20 View Post
    Now I wouldn't bother with the adaptor on the leather sealed piston to convert to a synthetic seal for three good reasons.

    1) John Knibbs is knocking out synthetic sealed Pistons complete with seal at 30.

    2) The adaptor adds 27grams to an already heavy piston.

    3) The adaptor reduces the already short stroke of the leather sealed piston by another 4mm.


    Here's the three strokes and weights of the three setups :-

    Factory Synthetic sealed piston ------------- 69mm stroke - piston weight 264g

    Factory Leather sealed piston --------------- 65mm stroke - piston weight 294g

    Leather sealed piston adapted to synthetic - 61mm stroke - piston weight 321g


    Saying all that I do like to start off with the old leather sealed piston as you can machine the nose back easily to end up with a lightened piston with a 71mm stroke.




    All the best Mick
    Sorry, but did I read that right.

    Are they made of nylon or carbon fibre for example.

    Does the reduced weight of such a piston make for a much smoother action?

    Or did you mean their own metal pistons with a synthetic seal?
    Last edited by T 20; 13-01-2017 at 03:50 PM. Reason: Fixed it for you Arthur
    Arthur

    I wish I was in the land of cotton.

  9. #54
    Join Date
    May 2008
    Location
    Quigley Hollow, Nuneaton
    Posts
    8,968
    Quote Originally Posted by Arthur John Smithsplease View Post
    Sorry, but did I read that right.

    Are they made of nylon or carbon fibre for example.

    Does the reduced weight of such a piston make for a much smoother action?

    Or did you mean their own metal pistons with a synthetic seal?

    Sorted it for you Arthur

  10. #55
    Join Date
    Apr 2002
    Location
    Bolton
    Posts
    12,249
    Thanks a lot.

    Thought it was probably a slip of the pen.

    But you never know.

    Arthur

    I wish I was in the land of cotton.

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