Page 3 of 4 FirstFirst 1234 LastLast
Results 31 to 45 of 57

Thread: Sizing seals in springers

  1. #31
    Join Date
    Jan 2007
    Location
    Plant City FL, 22 miles east of Tampa
    Posts
    1,453
    Quote Originally Posted by Vernal View Post
    I seem to have learned a lot about TX cylinders from this thread, as well as about sizing seals. I certainly was fooled by the cross hatching into assuming it had ben properly honed, but I noticed the tube has clearly been rubbing oppsite the shoe recess. I have no internal mike to check with, but the gun was running with only a few fps variation with the old piston and seal, so any variation in diameter shouldn't be a problem. It is now back together with a tight (but not ridiculously tight, as it was out of the box) seal, but only giving me 9.5 with 42mm preload, I suspect due to the tight seal. I'll put some pellets through it in the garden tomorrow, then see if that improves things.
    I don't think I am brave enough to try Tony's idea of boiling the whole assembly - has anyone tried it?
    Don't worry too much about the comp. tube since they are probably as good or better than anything else out there. There can always be a bad one, but I had one professionally honed and it was very near perfect, from the factory except for the ABT notches. Still only had a 9 fps spread with 20 pellets straight from the tin. Not sure if they are still this good as this was a 20 year old Mark3. Won a couple of state titles and shot many sub .5" groups at 50 m with this gun. The divot on the inside that is just opposite the cocking shoe recess on most tubes isn't a problem because it isn't in the swept area of the seal.

  2. #32
    Join Date
    Apr 2012
    Location
    Retford, Notts
    Posts
    37,287
    Quote Originally Posted by Shed tuner View Post

    You little tease, you. TonyL will be getting ever so excited (but they do look good)
    You know me so well, JB.

    I'll be very interested to get to know more about these rings, though.

    BOING!
    THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
    NEXT EVENT :- May 17/18, 2025.........BOING!!

  3. #33
    Join Date
    May 2011
    Location
    A few miles east of Nottingham
    Posts
    556
    Quote Originally Posted by NickG View Post
    Michael I have a selection of used tx seals Shall U send you one, I can select one and try it in a brand new tube I have here .
    That would be really kind thank you Nick, and would let me find out if the seal really is the problem before I go on to mutilate anything else.
    Last edited by Vernal; 20-10-2020 at 04:44 PM.

  4. #34
    Join Date
    May 2011
    Location
    A few miles east of Nottingham
    Posts
    556
    Nearly half a tinful through oday, and still 9.9 _ time for a seal change

  5. #35
    Join Date
    May 2011
    Location
    A few miles east of Nottingham
    Posts
    556
    Quote Originally Posted by Shed tuner View Post
    if you are building this for benchrest, and you are shooting one holers, I'd leave it alone
    The story of my life I suppose - never know when to stop!

  6. #36
    Join Date
    Nov 2013
    Location
    wimborne
    Posts
    866
    Quote Originally Posted by Vernal View Post
    The story of my life I suppose - never know when to stop!
    stop when you start going backwards

  7. #37
    Join Date
    Dec 2011
    Location
    coventry
    Posts
    1,819
    Quote Originally Posted by Vernal View Post
    That would be really kind thank you Nick, and would let me find out if the seal really is the problem before I go on to mutilate anything else.
    Ok will look one out tomorrow

  8. #38
    Join Date
    Apr 2002
    Location
    Near Wimbledon, SW London, or Lusaka, Zambia
    Posts
    26,987
    have you checked your breech seals ? Not sure how old the gun is, but that can compress and go hard over time...
    Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.

  9. #39
    Join Date
    May 2011
    Location
    A few miles east of Nottingham
    Posts
    556
    Quote Originally Posted by Shed tuner View Post
    have you checked your breech seals ? Not sure how old the gun is, but that can compress and go hard over time...
    Replaced them shortly after I bought the gun a few months ago.

  10. #40
    Join Date
    Mar 2006
    Location
    Worcester
    Posts
    22,222
    Quote Originally Posted by Vernal View Post
    Replaced them shortly after I bought the gun a few months ago.
    On reading the thread, I'm not sure of you have an AA or HW piston seal, but with a Mk.2 piston rod and Mk.3 mainspring, 41mm of preload should get you comfortably over 11 ft. lb. with the AA seal. a little more with the HW, unless air is leaking somewhere.

    As Jon suggests, I'd look again at breech seals and, if you are sure they're OK, remove the piston and cylinder, then test for air leakage past the cylinder end plug thread by sealing the outlet with your thumb and manually pushing the piston up the cylinder.

    Well worth persisting with; TX200s with 85mm strokes and Mk.3 springs took the top three places at the UKAHFT national recoil championship last year.

  11. #41
    Join Date
    Apr 2002
    Location
    Near Wimbledon, SW London, or Lusaka, Zambia
    Posts
    26,987
    Quote Originally Posted by BTDT View Post
    Well worth persisting with; TX200s with 85mm strokes and Mk.3 springs took the top three places at the UKAHFT national recoil championship last year.
    back in the day (not back in your day Jim, but in my more recent past )I took many titles with my home tuned TX200 HC - guess what ? 86mm stroke No doubt it's a sweet spot for these rifles.
    Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.

  12. #42
    Join Date
    Mar 2006
    Location
    Worcester
    Posts
    22,222
    Quote Originally Posted by Shed tuner View Post
    back in the day (not back in your day Jim, but in my more recent past )I took many titles with my home tuned TX200 HC - guess what ? 86mm stroke No doubt it's a sweet spot for these rifles.
    Back in my day?

    I can think of a few more titles you richly deserve

    85mm or thereabouts of stroke gives enough air mass and enough available piston stroke to avoid overly high peak pressure and temperature, so it's not stressed in the low to mid 11 ft. lb. region.

  13. #43
    Join Date
    Apr 2012
    Location
    Retford, Notts
    Posts
    37,287
    And, talking about "back in the day", showing how right the HW77 prescription was for sub-12, back in the early 80s. With a tad less stroke, too.
    THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
    NEXT EVENT :- May 17/18, 2025.........BOING!!

  14. #44
    Join Date
    Apr 2002
    Location
    Near Wimbledon, SW London, or Lusaka, Zambia
    Posts
    26,987
    Quote Originally Posted by TonyL View Post
    And, talking about "back in the day", showing how right the HW77 prescription was for sub-12, back in the early 80s. With a tad less stroke, too.
    yes, but it had a shorter (and smaller dia) TP, so less lost volume..
    Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.

  15. #45
    Join Date
    May 2011
    Location
    A few miles east of Nottingham
    Posts
    556
    Quote Originally Posted by BTDT View Post
    On reading the thread, I'm not sure of you have an AA or HW piston seal, but with a Mk.2 piston rod and Mk.3 mainspring, 41mm of preload should get you comfortably over 11 ft. lb. with the AA seal. a little more with the HW, unless air is leaking somewhere.

    As Jon suggests, I'd look again at breech seals and, if you are sure they're OK, remove the piston and cylinder, then test for air leakage past the cylinder end plug thread by sealing the outlet with your thumb and manually pushing the piston up the cylinder.

    Well worth persisting with; TX200s with 85mm strokes and Mk.3 springs took the top three places at the UKAHFT national recoil championship last year.
    I am using an AA seal,new from Chambers, but it is still much tighter than it seems should be. I had the same problem problem when I carried out your "simple tune " on my LGV,and you were kind enough, correctly, to point out then that the trouble was likely to be a tight seal. Resizing the seal, very time consuming, completely solved the problem, which is what caused me to start this thread in search of the best way to resize a seal. Nick G is kindly going to send me a run in seal which should confirm that the seal is the problem, or tell me to look elsewhere.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •