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Thread: Operation TX

  1. #31
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    Quote Originally Posted by Jon Budd View Post
    Taking the port to around 3.4/3.5 would be perfect if it's still full length
    It was 3.5mm and full length before I started Jon

    And I think you're right in saying that was perfect --- there's some funny things I've noted on the SCR as well changing from the AA seal to the Weihrauch seal.

    I'll post these up when I've calculated them.



    All the best Mick

  2. #32
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    Quote Originally Posted by T 20 View Post
    It was 3.5mm and full length before I started Jon
    Bloody tinkerer's

  3. #33
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    Quote Originally Posted by 18 Wheeler View Post
    heretic!


    Warning:I've seen this method used before. Forgetfulness or a surreptitious technique to move in?
    Don't think I haven't tried..... I've left an axe, a chair, and a trolley without success Mick did sharpen the axe for me though.

    Other kind mates returned the rest, at the next bash.
    Seize the Day! Quigley Hollow is a great place to start.

  4. #34
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    Quote Originally Posted by T 20 View Post
    It was 3.5mm and full length before I started Jon

    And I think you're right in saying that was perfect --- there's some funny things I've noted on the SCR as well changing from the AA seal to the Weihrauch seal.

    I'll post these up when I've calculated them.



    All the best Mick
    Doh... yeah, std size is 3.7 / 3.8mm. Taking it down to 3.4 will be much the same as shortening and keeping at 3.8

    How come yours was 3.5 ? That's not a std size, unless the v. early ones were smaller ?
    Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.

  5. #35
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    Quote Originally Posted by Jon Budd View Post
    Doh... yeah, std size is 3.7 / 3.8mm. Taking it down to 3.4 will be much the same as shortening and keeping at 3.8

    How come yours was 3.5 ? That's not a std size, unless the v. early ones were smaller ?

    The serial number of this one is 9087 Jon and the transfer port was definitely 3.5mm as standard.


    Quote Originally Posted by T 20 View Post
    There's some funny things I've noted on the SCR as well on changing from the AA seal to the Weihrauch seal --- I'll post these up when I've calculated them.

    Well I've had my Verniers and calculator out and it gives a bit more detail as to why the Walther piston with HW seal works so well in the TX.

    The front of the TX piston has a recessed steel centre section that acts as an arbor for the standard TX seal, this recess is 15.5mm diameter X 0.9mm deep having a volume of 0.17cc.

    My transfer port at 3.5mm X 9.8mm long having a volume of 0.094cc.

    My reduced port at 3.0mm X 9.8mm long having a volume of 0.069cc

    So :-

    The total lost volume using a TX seal = 0.17 + 0.094 = 0.264cc

    The total lost volume using an HW seal = 0.094cc


    The Static compression ratio of my TX with 41.3cc swept volume = 41.3/0.264 = 156:1 SCR

    The SCR with Walther piston and HW seal at 37.4cc swept volume = 37.4/0.094 = 394:1 SCR

    SCR with the trans port reduced to 3mm with 37.4cc swept Volume = 37.4/0.069 =542:1 SCR


    So looking at the figures now gives a bit of a clue as to why reducing the swept volume using a HW seal increased the power using the original spring set up.

    Next thing I'll do will be to open the transfer port back out to 3.5mm and reduce the preload by 3mm by chopping a closed coil off the spring.



    All the best Mick

  6. #36
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    Nice one Mick...

    yeah, I think that's why the TX seal is so bad, just too much lost volume in there. Ironically enough, it's less of an issue on the long-stroke mk3, but it ruins the mk1/2.

    On my SR (mk2) you can't change the rod length or you mess up the SR mechanism (which relies on the rear edge of the piston skirt being in the same place), so I simply switched to HW nose, shortened the port 2mm, and it's sweet as now... stroke has gone down from 82 > 77 (seal height + nose) but the SCR is actually higher, and so it feels much softer.
    Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.

  7. #37
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    Quote Originally Posted by Jon Budd View Post
    Nice one Mick...

    yeah, I think that's why the TX seal is so bad, just too much lost volume in there. Ironically enough, it's less of an issue on the long-stroke mk3, but it ruins the mk1/2.

    All Diana type seals seem to suffer the same loss, Jon

    I remember someone describing how he filled the central void with liquid rubber to raise the SCR on a TX, I can understand why now.



    All the best Mick

  8. #38
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    Excuse me, please, for reviving this thread.

    Just searched it out and thought I had better ping it up to page one for a while (a) as I have had the pleasure of using this gun at the April and June Bashes and IT IS SUPERB and, (b) having just got a TX, wanted to refresh myself with the details, folks.

    May help a few others, too.....
    THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
    NEXT EVENT :- May 4/5, 2024.........BOING!!

  9. #39
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    hi, which piston seal is the best for the mk2,or is the standard 1 ok. atb mick

  10. #40
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    Just thought I'd revive this yet again re current thread on TX tuning.
    THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
    NEXT EVENT :- May 4/5, 2024.........BOING!!

  11. #41
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    Quote Originally Posted by TonyL View Post
    Just thought I'd revive this yet again re current thread on TX tuning.
    Oh Tony you scamp!

  12. #42
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    Quote Originally Posted by T 20 View Post
    But you told me they were kilts that you were both wearing in honour of your Scottish ancestors.

    And I didn't like to say at the time but I thought that tossing the Caber competition looked a bit dodgy as well.
    Hang on a minute... did yooz aw day this without a single Donald present? I'll bring some SNP badges with me next time !😁😁
    Donald

  13. #43
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    Quote Originally Posted by Shed tuner View Post
    Nice one Mick...

    yeah, I think that's why the TX seal is so bad, just too much lost volume in there. Ironically enough, it's less of an issue on the long-stroke mk3, but it ruins the mk1/2.

    On my SR (mk2) you can't change the rod length or you mess up the SR mechanism (which relies on the rear edge of the piston skirt being in the same place), so I simply switched to HW nose, shortened the port 2mm, and it's sweet as now... stroke has gone down from 82 > 77 (seal height + nose) but the SCR is actually higher, and so it feels much softer.
    *zombie post revival*

    Tuning an SR? Isn't that a bit like having a dog and barking yourself?

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