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Thread: Help Needed. 1935 Benjamin Franklin Air Pistol Repair

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  1. #1
    Join Date
    Aug 2008
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    Twickenham
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    364
    Thankyou. I am not familiar with these airpistols so this is very helpful.
    I did wonder if it was lead based solder but thought it would not be robust enough. Should make it more straightforward to repair :-)
    Next job - source the tool.

    Thanks again
    Steve

  2. #2
    Join Date
    Jan 2007
    Location
    New Mills, High Peak.
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    3,895
    Quote Originally Posted by Mobiasstrip View Post
    Thankyou. I am not familiar with these airpistols so this is very helpful.
    I did wonder if it was lead based solder but thought it would not be robust enough. Should make it more straightforward to repair :-)
    Next job - source the tool.

    Thanks again
    Steve
    Not that difficult to make, I made mine from square key steel, though I have read of folk grinding an old socket to suit.

    Dimensions here: http://www.mcarterbrown.com/forums/s...ensions-2.html

  3. #3
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    Aug 2008
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    Twickenham
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    I dont have the tools to manufacture so will need to purchase the tool.
    Steve

  4. #4
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    Aug 2008
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    Peds contacted and purchase made. MANY thanks. Steve

  5. #5
    Join Date
    Jul 2012
    Location
    Portland, Oregon
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    725
    Yep. A pretty common occurrence with Benjamin pistols and rifles. Saw a lot of these at the local repair shop.

    Years ago, I talked to a local airgun mechanic who repaired these. As I recall, he stressed the importance of getting all of the old solder off. Then, standard brass plumbing flux and solder. Used a standard propane torch.

    Most of the conversation involved details about how the job had to be done right and.... I can't really recall much.. but, there was one bit about how the gun can be improperly soldered in such a way as to put stress on the barrel, which would cause the gun to flex with temperature differences. Vividly recall how he described how such a gun, soldered and left under tension, where he heated up the breech (or muzzle?) and that the gun eventually "popped" releasing the tension.

    The Benjamin design, with both the muzzle and breech soldered hard to the compression tube, as we can see, fails. Not sure if there is any real data but I recall speculating either the gun being dropped or even being exposed to the sun. A gun with a barrel under tension (as above) exposed to the sun would seem to be an ideal candidate for this type of failure.

    Crosman rifles and pistols of the similar design (109-120) the muzzle end sits inside a bracket brazed to the lower tube so this all but never becomes an issue.

  6. #6
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    Aug 2008
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    An afternoons fettling went well.


  7. #7
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    Aug 2008
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    Holds pressure well too. :-)

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