HELGA GOES IN FOR MAJOR SURGERY!

Forums PCP Airguns HELGA GOES IN FOR MAJOR SURGERY!

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    CHUCK
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    Helga was having trouble breathing so the surgeon had to go in and open up the transfer port in her rear block, as well as the transfer port in her barrel inlet and valve house. Now she is breathing better than ever! Now on just a little breath of air she can spit out pellets at much higher velocity, and take complete advantage of her Polish Miracle Power Plenum made by none other than Master Michal Osyda himself!

    This Polish plenum truly worked a miracle for Helga and its elegance is in its simplicity. Just an over sized inline plenum with a valve house that has a 7mm valve seat and a larger spire seal to accommodate it…allowing full use of all her existing hardware! Here are some pictures of her in surgery…I have to warn those that have weak stomachs not to look at them because they are sort of scary!  đŸ˜˛

     

     

     

     

    • This topic was modified 1 week ago by CHUCK.
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    Glem.Chally
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    Wow, thats an undertaking.  Any results Chuck? 

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    Chris1973
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    Nice work chuck!I 👍đŸģI  am ready to make the same port openings but I managed to find finally a new rear block and valve housing in case something go wrong. The grub screw i will use is 10 mm . I really like the way you polish it. For sure will be there a smooth air path. Did you open the rear block tp 8mm? I am looking forward for your results!

     

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    CHUCK
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    Glem.Challey: Just got her all back together tonight and she is holding air with no leaks! So tomorrow I will go shoot her over my chronograph at the same reg pressure as before to see if this made any difference or not. Wish me luck! đŸ˜†

    Chris1973: In my .30 cal. rear block the transfer port hole was 7mm I believe, and I wanted to open it up to about 8mm because I had previously enlarged the hole in my barrel inlet to 7.5mm.  So I looked at this chart and discovered that "M10 x 1.50" requires a drill bit size of 8.50mm! Even Better! So I went to Home Depot today and bought an M10x1.50 tap and bit combo for around $10. I figured the drill bit would make the transfer port hole 8.5mm, and then I could just tap the hole in the block for M10x1.5mm threads…but where to get a 10mm x 1.5 set screw?

    Then I remembered that last year I had to order one for a gun I was working on but that on Amazon the only ones I could find came in a package of 25! So I rumaged around in my old parts/junk box and lo and behold I found the whole bag of M10x1.5 socket head grub screws! Well then the next problem was that these screws are 10mm long and the old set screw in the block was 8mm long…so instead of trying to make one of these screws shorter, I just used a 13/32" bit to make the hole in the magazine bracket larger so as to fit over the top of the set screw, and still allow the bracket to sit flush flat on the bottom of the block the way it is supposed to. (see photos below) You can see that the 13/32" hole just barely missed the two rear screw holes of the magazine bracket…Whew! đŸ˜˛ đŸ˜† 

    You guys have to laugh with me when you stop and think I only have a Makita battery drill and a little tiny drill press vise that I clamp to my glass top desk…and a junk box of various old drill bits out in my work van…unbelievable the way things just fall into place sometimes! Anyway Chris that is how I did it!

    I used an 8.5mm drill to enlarge the transfer port hole in the block, a 5/16" drill (same as 8mm) to enlarge the hole in my brass barrel inlet to 8mm, and an 11/32" (same as 8.73mm) drill to enlarge the transfer port hole in my valve house, and the 13/32" drill to enlarge the hole in the magazine bracket. I already had a 125 grain hammer weight installed before…or 8 grams if you please. I find that when it comes to hammer weights Helga likes big ones!  😁😂

    PS…Chris, on Google I read about a very cool trick to prevent the bit from grabbing in the hole causing the drill motor to try and break my wrists! You take a flat file and just make a couple strokes in one direction on the two sharp edges at the tip of the drill bit to dull them slightly…and Viola! just like magic it quits grabbing and makes nice little metal chips! đŸ˜ƒ

    • This reply was modified 1 week ago by CHUCK.
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    sonny
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    Brilliant! 

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    Chris1973
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    A very very big thank you Chuck .You could not describe it better. It helps me a lot to avoid mistakes in tapping. So far I have all the rest modifications in my impact and I am shooting 65gr NSA at 950 f/s but I didn’t touch the real block yet. Now we are sitting closed in the house is the right time.We are looking forward for your results !!!👍đŸģ
     

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    CHUCK
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    Okay guys…I took her out to shoot her today and she blew out the tiny o-ring on the tip of the valve pin…and it appears that the valve house itself has slightly moved to the rear into the mag well…both not good news…So back to the drawing board! đŸ˜Ĩ More news as it becomes available…I hope I don't have to beg Ernest to bail me out again…đŸ˜Ŧ

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    CHUCK
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    I discovered the problem was caused by…ME! đŸ˜˛ 😖 It turns out that when I drilled the transfer port hole in the plenum larger with the 11/32" drill the tip of the bit damaged the entrance to the little "tunnel" where the tip of the valve pin goes and it is cutting the little tiny o-ring on the tip. I tried to save it but I think its hopeless so I am starting out with a new valve house that had the valve seat opened up to 6.8mm by a friend in Michigan recently. Whew! Thank God I had this spare one! I am kicking myself in the ass for not ever going out and buying a small drill press to use on projects like this! I will open up the transfer port on this last valve house now with my Dremel Tool & one of the cone shaped stone things…wish me luck!

    Chuck

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    CHUCK
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    Oh Crap! Now the 10mm grub screw is too big for the flat spot cut out on the new valve house! đŸ˜ą Thankfully I can make it a little smaller with my Dremel Tool…I'm almost afraid to ask what next? Wow! You can't imagine how hot the tip of that screw gets when you grind it down like that…😡

    • This reply was modified 1 week ago by CHUCK.
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    Airgun-hobbyist
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    Chuck, be sure that you make that shouldered screw precise.  It holds the world together back there.  If it lets go of that valve housing the gun will bend up like a banana. 

    Shortening the return spring give you more air space and less turbulence as well.  To do this you cut the spring a little bit longer than the shoulder on the valve stem and behive it down to the smaller stem's diameter.

    If you end up getting a new block and valve housing to rework, here is the Dremel tool bit I used to open my inner block port up to 8mm.  It slides right in past the threads so you can do the port work inside, and use the original shouldered grub screw to hold everything in place.

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    CHUCK
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    Wow thanks for the info about the Dremel bit, and yes I cut my valve pin spring shorter per Ernest's video the first time I took her apart, which seems like years ago now…but I just put her all back together and instead of showing 1040 or 1050 ft/s on Max she is now showing 975 which means I am going backwards…đŸ˜Ĩ Well back to the drawing board again! 

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    Chris1973
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    I am sorry things didn’t go well Chuck.

    I  can understand that is most possible to damage the small tunnel that seals the tiny oring . Even if you use smaller  diameter drill 8mm in a vertical drill base I think is very difficult the small tunnel to remain untouched. So slowly with a dremel seems to be a better idea for the VH transfer port . 
    But I can’t understand why the whole valve house moved slightly back from its position. 
    When you made the new threads for the grub screw what went wrong ? It supposed that you used a bigger diameter 10m screw and it should keep the vh tight in position. 
     

    Airgun hobbyist

     if I will use the type of Dremel you recommend ,it will slide safe through the threads but that means that I have to mill the tp hole slowly without know how precise I will make the hole. For sure a vertical drill in a base with a diameter of your choice will make a perfect hole but is coming after the issue with the new threads for the grub screw. That’s why I am trying to understand what went wrong with chucks thread work .

    It would be more easy for me to open the rear block tp in a vertical drill base but now I hesitate if the M10 grub screw will tight properly the VH. 

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    CHUCK
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    I had to put this project aside for a while so I could take care of some other things that needed my attention – Honey Do Projects…😖 I will keep you posted on progress soon I hope!

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    Airgun-hobbyist
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    Chris1973

     

    It would be more easy for me to open the rear block tp in a vertical drill base but now I hesitate if the M10 grub screw will tight properly the VH. 

    That bit is easy to use and makes precise work.  Grind a little at a time, and then test fit the parts to see if the ports match.  If it needs more in an area, open it up more.  No need to make extra work with a drill bit, threading, making new shouldered grub screw, or have potential gun failure from things that do not have to be modified.  

     

    @chuck the ball Dremel bits work nice to modify the housing ports instead of just drilling it out.  You create way better air flow this way; like porting the cylinder heads on a dragster.  Smooth the corners and ramp the back edge so there is a nice transition.īŋŧ

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    CHUCK
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    Ah: Yes you are certainly right about that…for many years I have used my Dremel Tool with those bits to modify the transfer port in the brass barrel inlets when tuning guns for people, and of course during the last several months I also use my Dremel to modify the valve house transfer ports. But….while I had my drill out and my pile of drill out on the table I just couldn't resist the temptation to use my drill to enlarge the transfer ports in both my valve house and my barrel inlet! đŸ˜– I guess since the work on the rear block and mag bracket went so well I just couldn't stop drilling… 😆(love my Makita).

    So the upswing is I ruined one valve house and threw it away…and because I am too stubborn and stupid to learn from my first mistake of course I had to try again and ruined a second valve house…Whew! But of course that is only after I had drilled the transfer port in my barrel inlet larger with an 8mm drill and then later discovered the nose of my pellets are slightly dropping down into the hole and getting damaged…which yes means I ruined it also! I amaze myself sometimes with how dumb I can truly be!

    But trial and error are the way I have learned what to do when tuning airguns to make improvements, and sometimes more importantly how I have learned what not to do! I don't get too upset with myself when I pull some bone headed stunt because I seem to learn so much from all my mistakes that many times I am later glad it happened. And so many times a friend sends me a gun with a problem and I look at it and realize immediately that they caused the problem, the same as I had somewhere along the line. Its always funny when I call them and tell them exactly what they did to cause the problem and they wonder if I am phsycic or something! đŸ˜ƒ

    I am waiting for the mailman to show up today with a new barrel inlet I had given to a friend and had to call him and ask for it back…but for now I have to go start making the sauce for our spaghetti dinner this afternoon…and then help Karen clean the bathroom…and whatever else is on her freaking to do list today…đŸ˜ĩ

    • This reply was modified 1 week ago by CHUCK.
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