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Thread: How to make a tap, to make a tool, to fix a Sheridan

  1. #11
    Administrator AirGunEric's Avatar
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    Quote Originally Posted by SeanMP View Post
    What's more of a PITA though is 3/4 of my last post seems to have disappeared.....wth happened there I wonder.
    What are you talking about? The software shouldn't eliminate parts of posts.
    I'd say I care- but I'd probably be lying...


  2. #12
    Senior Member SeanMP's Avatar
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    It's not the software. The same thing has been happening to my emails when I insert a lot of pics
    Sean

  3. #13
    Administrator AirGunEric's Avatar
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    ? Your computer is stripping things off everything ?

  4. #14
    Senior Member SeanMP's Avatar
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    Seems that way whenever I attach a lot of pictures
    Sean

  5. #15
    Senior Member SeanMP's Avatar
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    So finally getting back to fixing up the missing post and closing off

    The next step to making a shop made tap is to mill or grind the cutting edges. This is actually not as racey as it looks. I'm sure you could make a usable cutting edge on a bench grinder. The farther past the centerline the more aggressive the cutter will be.
    IMG_0372.jpg

    Then the tap needs to be hardened and tempered the usual way
    I protect the fine threads with this borax and clay mixture
    IMG_0374.jpg

    And here is the finished tap in action
    IMG_0376.jpgIMG_0375.jpg

    As seen in the picture the opposite end of the tool is turned down to 3/8" (not required but looks good) and then a .250-.255 hole is drilled .750 deep for the minor tap diameter. The tap in the picture is not ground very aggressively and as such needed to have the chips cleaned off every couple of turns
    Sean

  6. #16
    Senior Member SeanMP's Avatar
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    Here is a pic of the finished tool just before I drilled a 1/4" hole right in the center for a turning bar and then hardened the working ends
    IMG_0377.jpg

    Here is the cap nut freshly removed from the valve assembly. I'm not sure if it's the norm but it took everything I had to turn that nut out. The first attempt bent an ordinary 1/4 tool punch at 30 deg....Todd was a witness to the punch. I ended up hardening a piece of 1/4 drill rod to use as a turning bar.
    IMG_0378.jpg

    Then the tool is turned around and screwed onto the threaded stub on the valve. Wiggle and pull your guts out until the lead seals break free. And here is whats inside.

    IMG_0380.jpg
    Sean

  7. #17
    Senior Member SeanMP's Avatar
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    So as previously mentioned parts for this thing are basically unobtainable here. However all the parts are replaceable with modern alternatives with the exception of the check valve. This is a simple flat disc cup 0.405 OD x .110" thick. The original is made of brass with a (delrin?) insert. It can be replaced by a simple piece of delrin of the same dimensions. I choose to remake the piece as it was originally because this is a customers rifle.
    IMG_0383.jpgIMG_0381.jpg

    The valve poppet can be replaced by a disco poppet. I had one but unfortunately the old seat was so cockeyed that it ruined the my only disco poppet so I had to make one. I do this by drilling an undersize hole in the delrin then spinning the stem at warp speed while pushing the delrin head on. This fuses the two pieces together then you machine the face and dress down the head to the right shape
    IMG_0386.jpg

    The lead seals can be replaced by (2) 015 orings. The first oring fits onto the valve as seen in the last pic. The second oring gets squashed between the cap nut and the valve core. Lots of threads out there say this seal is unnecessary but if it's not there the transfer port will leak.
    Oring on cap nut.jpg

    From this point the only difficulty is getting the little tab on the valve core lined up with the slot in the body that's soldered into the tube while simultaneously compressing the valve core spring and screwing in the cap nut...tricky but it works with the tool.
    Sean

  8. #18
    Senior Member SeanMP's Avatar
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    Last thing to do on this rifle was replace the pump cup.

    The rubber seal itself is the same OD as a modern Benjamin 392/397 so just a simple matter of popping the old one out and popping a new one in.......

    WRONG!


    The bright lights at Sheridan decided to crimp the rubber seal into the steel cup with the most complicated crimping die I have ever seen.
    photo_2.jpg

    So a new cup had to be made to accommodate the pop in seal. I could have made it out of anything really but I chose brass.
    Turn down stock to 0.765 OD
    Drill a center hole with a #3 drill (tap drill for 1/4"-28)
    Hollow the center of the cup to 0.600" ID to a depth of .250"
    then create a lip to hold the rubber seal by opening up the ID of the cup to 0.640" out to within 0.025" of the edge.
    photo_1.jpg
    Part the piece off at .400" thick and then tap the remainder of the #3 hole to 1/4"-28. Then face it off to 0.375"
    photo.jpg
    Install the cup and button it up.
    Last edited by SeanMP; Feb 22 2013 at 09:40 PM.
    Sean

  9. #19
    Moderator rsterne's Avatar
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    I love watching a craftsman at work.... *grin*.... beautifully done, Sir!!!

    Bob
    Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
    Airsonal: Too many to count!

  10. #20
    Senior Member sholo's Avatar
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    Wow..."nightmare" for sure!

    I'm no machinist (long, long way from it), and even I can appreciate what just took place for what should have been a "simple fix" on most other guns.

    Like Bob said - Beautiful job!!!


    Todd
    Todd

    Don't sweat the petty things, and don't pet the sweatty things!

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