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mogogear
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Joined: 01 Feb 2008
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Location: Portland Oregon
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 Posted: Wed Apr 11, 2012 12:56 am Post subject: |
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Man o Man I like the simple way you portrayed that..
No "ball socket" needed- just a ball in a cylinder!!!
The design sure would give the casual observer the feel of a "skewed" gudgeon pin..
Easy to machine - except the small diagonal slot in the "ball" collar?? Unless this internal fitment is made first and then soldered into a "hollow piston body"
The ball could just be held in the cavity by the pin
Dean you are my hero!!
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Dean W
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Joined: 28 Jul 2010
Posts: 6271
Location: N. Idaho, USA
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| Posted: Wed Apr 11, 2012 4:47 am Post subject: |
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| mogogear wrote: |
Dean you are my hero!! |
That's really nice Greg, but you should set your sights somewhat higher! 
Now, I think that angled slot could just be milled into the bottom of the piston, whether you put it directly into the
piston skirt or you make a protrusion on the bottom of the piston like in my scratch-up drawing.
Another way would be to make the piston and the twisty part as separate assemblies, then slide the twisty thing
up in the piston skirt and solder it.
That diagonal slot has no curve to it. Just straight, and has one on both sides. This is the only really simple way
I could come up with, and I'm not saying that's how they did it. It does make for an easy machining step, which
seems to be mandatory for a toy engine that would sell for a reasonable hobby price. It takes no fancy machining
setup. Just a vise at an angle on the mill, mount the piece, plunge in, crank the mill table, withdraw the end mill.
The wrist pin can be an interference fit in the ball end and will hold everything in place.
I suggest this because some of the other versions put up here seem to need complicated mill setups, and we
have to keep in mind that these engines were made before any CNC machinery. It is very possible that the
rotating piston is effected by even simpler means than this.
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Dean Williams
http://www.deansphotographica.com/machining/projects/projects.html
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Lenny
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Joined: 13 Sep 2009
Posts: 714
Location: South Queensland
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| Posted: Wed Apr 11, 2012 9:11 am Post subject: |
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| Dean W wrote: | Just a suggestion, guys; Maybe over thinking this a bit. If the top end of the rod is a ball shape, and it has a small pin
through the center of the ball, all that is needed to rotate the piston in the cylinder bore would be a simple straight diagonal
slot in either the side of the piston, or the carrier for the "ball end" of the con rod. As the rod travels up and down, that pin
will rotate the piston simply by traversing up and down that diagonal slot. The side-to-side swing of the rod changes the
position of the end of that little rod.
Sez me, anyway. It's easy enough to be wrong about this whole thing.
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I like your train of thought on this Dean . I also had a similar
idea in mind . The difference being , the diagonal slots are cut
into the ball and the pins fitted into the sides of the socket .
Just an idea . 
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kno3
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Joined: 21 Mar 2009
Posts: 816
Location: Bucharest
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| Posted: Wed Apr 11, 2012 11:02 am Post subject: |
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This is indeed possible.
Anybody volunteers to have a piston of their Bowman-Bryant engine un-soldered for the advancement of forum knowledge?
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mogogear
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Joined: 01 Feb 2008
Posts: 8191
Location: Portland Oregon
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| Posted: Wed Apr 11, 2012 2:12 pm Post subject: |
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| kno3 wrote: | This is indeed possible.
Anybody volunteers to have a piston of their Bowman-Bryant engine un-soldered for the advancement of forum knowledge? |
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Mo (greg)
His Most Noble Lord Admiral Mo, the Apocalyptic of Old Tonbridge Wafers
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Roly Williams
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Joined: 02 Aug 2006
Posts: 12054
Location: Lambourn, Berks.
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| Posted: Thu Apr 12, 2012 12:00 pm Post subject: |
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Haynes publish workshop manuals for lots of things (not just cars), based on a full strip down and re-build. I wonder if they could be persuaded to do one of these? 
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Roly Williams
"Opportunity is missed by most people, mainly because it is dressed in overalls and looks like work" (Thomas Alva Edison) |
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jetex
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Joined: 14 May 2012
Posts: 1
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| Posted: Fri May 25, 2012 9:45 pm Post subject: |
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| I have been reading this thread with interest but it now seems to have come to a stop without us really knowing how the piston turns on the con rod. I had hoped that the people who have this engine would have shown more pictures of the top and bottom of the pistons as this may show how it was constructed. I had wondered if the con rod was dropped in through the top of the piston judging by the way the bottom end of the con rod is constructed. |
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mogogear
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Joined: 01 Feb 2008
Posts: 8191
Location: Portland Oregon
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| Posted: Fri May 25, 2012 11:04 pm Post subject: |
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First things first..
Welcome Jetex...good to have you here with us. You know it comes down to you almost need to unsolder the small bits to see exactly the HOW part of the question.....
They are so rare no one is willing to chance altering a valuable engine.
It would be such a keen engine to replicate a tribute version and get a set of drawings out for the engine to flourish again.. as you stated - we all thought and over-thought on this curious topic for a while...so close but hopefully a "parts " version that is already flawed can be found one day to de-construct and reveal all
So we are all just Waiting ....
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His Most Noble Lord Admiral Mo, the Apocalyptic of Old Tonbridge Wafers
http://gerddi.blogspot.com/ |
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