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Thread: The Bucket Foundry

  1. #4216
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    Quote Originally Posted by Grumph View Post
    Well, the McCulloch kart engines used two quarter inch capscrews into alloy rods at the big end without major problems. As do millions of industrial engines.
    Personally, I'd do inserts in the piston to increase the thread engagement area.
    I'd probably also either use hex head screws - or grind flats on round capscrews - to use a steel strip between the heads, bent up as a positive lock.
    A lot of industrial engines use hex headed big end screws with a bent up steel lockplate.
    Yep, helicoils with locking tabs on hex heads should be OK. I like that there's maybe 40% less gudgeon pin mass there too.
    Go soothingly on the grease mud, as there lurks the skid demon

  2. #4217
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    Yeah, well I've been trying to remember who tried that scheme (skirt separation) and the more I think about it the more it's coming back to me (so I need a little more time! - it's probably approaching 40 years ago!), but I'm beginning to think that the pin support "bosses"? were actually cast into the crown in order to separate them from the skirt to prevent distortion/ seizure . Whether or not there were gudgeon pin holes in the skirt I can't remember - sorry if it's all a bit vague - it is there somewhere ...... but anyway it's food for thought I guess!
    Possibly I'm combining (confusing) two separate designs stored in the archives of my mind!

    Addition:
    Found these while browsing for the elusive piston :-
    Maybe try something similar to this style (ignore the crown etc - that's a diesel piston) but the same idea, except the skirt would be a complete tube (with no holes in it) and of course a "slightly" smaller gudgeon pin! - possibilities?

    Sorry Neil, not trying to better your idea - just dreaming!

    Click image for larger version. 

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    Freedom of speech is important but if what we say is considered incorrect by our peers, they will quickly put us right.
    P.C. will eventually destroy our right to tell the truth.

  3. #4218
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    Locking

    What about two small pins in from the side with rearranged pillars with circlips Puts the pins in double shear, nothing to unwind .
    Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.

  4. #4219
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    Is there any advantage in being able to raise the pin height in the piston? With Neil's pedestal/cap arrangement you get to ignore the ring groves.
    Go soothingly on the grease mud, as there lurks the skid demon

  5. #4220
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    Quote Originally Posted by Ocean1 View Post
    Is there any advantage in being able to raise the pin height in the piston? With Neil's pedestal/cap arrangement you get to ignore the ring groves.
    The higher the gudgeon the longer the rod for a given engine height, w3hich gives potential for less rock and friction and HP per given dimensions. the rod length also alters the port timimg and the dwell and acceleration with the bigest effects arround tdc and bdc
    Also the higher the ring pack the higher the potential output (and decreased longevity...) but the gudgeon is not the limiting factor in ring pack placement in a 2t

    In Vietnam he laughs at Neils Knees snd flamable sheep and raises him not shoes and on the side of the road in the rain.
    \
    Note his multipurpose ramming tool. 27.50
    plus those with keen eyes will see him poor out of a US Military helmet. 32.30\

    For Will



    Kinky is using a feather. Perverted is using the whole chicken

  6. #4221
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    Husa,
    Fantastic video of Vietnamese foundry, not a single safety measure in sight! - those guys are unbelievable, they put guys like me to shame with their innovation!
    Did you see the quality of the castings? - brilliant, not a blow hole anywhere - that would be unthinkable!

    Will watch the second video soon.

    Later on:- Saw that one before and I liked it. - "Myford Boy's videos get the message across simply and cleanly, - no bullshit, in fact without as much as a word spoken!
    Freedom of speech is important but if what we say is considered incorrect by our peers, they will quickly put us right.
    P.C. will eventually destroy our right to tell the truth.

  7. #4222
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    Quote Originally Posted by WilDun View Post
    Husa,
    Fantastic video of Vietnamese foundry, not a single safety measure in sight! - those guys are unbelievable, they put guys like me to shame with their innovation!
    Did you see the quality of the castings? - brilliant, not a blow hole anywhere - that would be unthinkable!

    Will watch the second video soon.
    You will like this to then

    I was told once that the pressing tools and output is so fine in detail that occasionaly lazy factory workers used to thrown in a smoke butt and that would cause a blemish in the panel stopping work why a confused QC looked for the fault in the die.
    I dont know if thats true or not.
    But there is a a sort of pressing that is done with Rubber sheets that looks cool i have posted it before.

    ww2 version



    Some other hand forming show tools and methods



    Swede metals videos have nearly all been taken off.
    https://www.youtube.com/watch?v=YH3tHtADIkw

    https://www.youtube.com/watch?v=_H4zAfTuAXQ



    Kinky is using a feather. Perverted is using the whole chicken

  8. #4223
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    Wilder way

    Quote Originally Posted by Flettner View Post
    Grumph, you are getting old and cynical like me



    Another two stroke dream

  9. #4224
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    Quote Originally Posted by Niels Abildgaard View Post



    Another two stroke dream
    Yes, another thought I had. But for me this way with the caps is lighter, with my steel pin tapered and hollow. Because the pin is so much shorter I intend to thin the pin out some more, less weight still. My alloy caps don't count gor much weight.

  10. #4225
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    https://pdfs.semanticscholar.org/d48...c146bcac0a.pdf
    Protective Films on Molten Magnesium
    SF6 is used in substation switches as an inert gas to prevent arcing, its bloody expensive
    They also used it for torpedo's proposulsion despite its general inertness when sprayed over pure lithium it release's massive amounts of heat.
    From what i understand its cheap as chips in the USA.



    Kinky is using a feather. Perverted is using the whole chicken

  11. #4226
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    Neil are you planning on using a roller or plain little end bearing?
    Do you think the fixed gudgeon pin will Brinell from the rollers only working one side?
    Saying that I suppose you don't see it on the rod.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  12. #4227
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    That's impressive. My understanding is that it can be avoided by careful choice of roller size - such that each rollers arc of contact overlaps with the ones each side.
    Neil can of course float the pin. Either by clearancing it deliberately or by making it a cold interference fit - which becomes a floater when hot.

    I suspect you've been reading Irving. He's the only writer I've ever seen use the term "Brinelling" I once used it when talking to the very experienced precision grinder who was finishing a crankpin for me. He had no idea what I was talking about.
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  13. #4228
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    Quote Originally Posted by Brett S View Post
    Do you think the fixed gudgeon pin will Brinell from the rollers only working one side? Saying that I suppose you don't see it on the rod.
    It will occur on the pin first. Despite some elastic deformation the contact line between pin and roller is quite narrow because the two surfaces bend away from each other. The situation between rod eye and roller is more favourable because both surfaces curve in the same direction.
    You could use a cageless crowded needle bearing. Normally that is a bitch to fit, but in Neils system it can easily be put together before the pin is fitted in the piston.

    Quote Originally Posted by Grumph View Post
    Neil can of course float the pin. Either by clearancing it deliberately or by making it a cold interference fit - which becomes a floater when hot.
    Floating the pin would make the construction much more critical. It would also necessitate a provision for constraining the pin's axial movement. Remember

  14. #4229
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    It's a solution for a problem. And a solution looking for a problem.

    Stressing it, literally.

  15. #4230
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    Quote Originally Posted by Frits Overmars View Post

    Floating the pin would make the construction much more critical. It would also necessitate a provision for constraining the pin's axial movement. Remember
    Constraining the pin is relatively easy. Either full blind ends in the clamping pieces or partial "eyebrows" - neither of which would present a major machining problem.
    Or - if locktabs are used for the screws - extend them over the edge so to speak and use them to retain the pin.
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