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Thread: Frank Clarke – airgun genius. The conundrum of one of his last inventions.

  1. #1
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    Frank Clarke – airgun genius. The conundrum of one of his last inventions.

    One of the many puzzles in the field of vintage airguns is why Frank Clarke bothered to introduce a spring-loaded “pusher” loading pin into some of his first model Briton pistols. I have had a Briton with such a pin for many years and thought at first that the pin was just a one-off from an amateur hobbyist, but other examples have since come to light (possibly as many as five) and we can now be confident that the retractable pusher pin was indeed the brainchild of Frank Clarke.

    But it was a development that never really made the grade. The retractable pin screws into the breech in the usual way with these push-barrel pistols, and pushes the pellet into the barrel. Once it is screwed in place, the spring-loaded end knob can be used to push the pellet in even further. The knob then returns under spring pessure to seal the breech. The following picture shows a normal Briton pin, together with the spring pusher pin in its relaxed and compressed states.




    The puzzle is why did a Frank Clarke, an undoubted genius when it comes to air pistol design, bother with such a complication ? It would have been expensive to make compared to a traditional pin, and seems to achieve nothing that a normal pin can’t do. I have puzzled over this for some time and reluctantly came to the conclusion that it was an uncharacteristic lapse on his part and just a passing fancy that served no real useful purpose.

    Then one night, thinking about nothing in particular, out of the blue I had a flash of inspiration and I knew what the retractable pin was all about. Far from being just a whim on Frank Clarke’s part it was an extremely useful invention, brilliant in its simplicity. In fact it was something that should have been patented and fitted to other push-barrel pistols, so why he didn’t take it any further I don’t know.

    No, I am not going to tell what the real function of the retractable pin is – not yet anyway.

    I thought it would be interesting to challenge you, to see if you can pit your wits against Frank Clarke and work out what he was really up to. Like all good ideas that are really obvious once pointed out, it takes a genius like Clarke to spot them in the first place.

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    It gives a lower power option. Lowers the effective compression ratio, increases "dead space" volume and effectively shortens the barrel.
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    Don't think anyone would like to make these lower power than they already are. How does the air get by the larger diameter pin ?

    Baz
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    No, nothing to do with altering lost volume or power level. Much more significant than that.

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    In-built pellet sizer/former?
    Used to push the pellet past a transfer port?
    Rich.
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    Question

    I always thought that pushing a gas through a smaller opening made for higher presure!


    John
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    Does it allow 2 projectiles to be loaded? First one goes in then is pushed in deeper, out comes the pin and in goes projectile 2???
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    Thumbs up

    Quote Originally Posted by averageplinker View Post
    Does it allow 2 projectiles to be loaded? First one goes in then is pushed in deeper, out comes the pin and in goes projectile 2???
    That sounds entirely feasable!


    John
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    Perhaps to increase life expectancy of the threaded sections. If a pellet is pushed in then the pellet probe is offered up and then without screwing in,the plunger is pushed in pushing the pellet down far enough that as you screw the probe in there is no resistance from the pellet to increase wear in the thread. Over thousands of shots perhaps the inventor feared it would lead to excessive wear. The photo where it’s extended seems to show that the length of the extension is slightly longer than the thread which would make sense. Also the thread appears more tapered on the plunger version with a short collar,perhaps this helped keep the probe straight when loading as described rather than sitting awkwardly on the biting point of a deeper cut thread. Also with the pellet now forward of the transfer port a non returning fixed probe would be sitting in front of the port creating resistance & turbulence in the air flow.
    The plunger design sort of reminds me of a spring loaded Stauffer pot to look at.

  10. #10
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    I do like these collectible conundrums....

    As said above is it to push the pellet past the transfer port, then retract so as not to interfere with the airflow from the transfer port, as a normal insertor would remain partially covering the transfer port?

    Btw thanks for identifying one of these on a Briton I acquired, I had no idea what it was!

    Matt.

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    The machining, and maybe the materials, look different between the two items. I'd suggest that perhaps these were "after market" accessories, which would explain why they appear to be rare.

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    Always reckoned the pop-out pistol was more scientific than it was credited with!

    The pellet pusher allows a missile to be stationed muzzleward of the air transfer vent holes and it seals the breech. When the modified version is retracted, compressed air passes through the barrel transfer ports into an empty space previously occupied by the movable pellet pusher. A state of affairs that facilitates,maximum and undisturbed air flow behind a breeched missile.Thus increasing muzzle velocity.

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    Some very interesting and ingenious replies, but no one has hit the nail on the head yet. The function of the retractable pin is much simpler than you might think and is of real everyday practical value. It has been staring peope in the face ever since Quackenbush made the first push barrel pistol in the 1870's, but it took the genius of Frank Clarke 50 years later to see it.

    What I don't understand is why the idea was never picked up and used in all the many push-barrel barrels that have been / are being made ever since.

    I will leave you guessing a bit longer, as someone may yet have a flash of inspiration.

    You will kick yourself when you know the answer.

  14. #14
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    ggggr is offline part time super hero and seeker of justice
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    John--what is the length of the pin compared to standard--in both positions?
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  15. #15
    micky2 is offline The collector formerly known as micky
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    Quote Originally Posted by cinedux View Post
    The pellet pusher allows a missile to be stationed muzzleward of the air transfer vent holes and it seals the breech. When the modified version is retracted, compressed air passes through the barrel transfer ports into an empty space previously occupied by the movable pellet pusher. A state of affairs that facilitates,maximum and undisturbed air flow behind a breeched missile.Thus increasing muzzle velocity.
    l would have gone along with this one. but it seems like it is not.

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