[PSUBS-MAILIST] q ball arm

[Alan via Personal_Submersibles]

Brilliant discovery Hank,
I wonder if the ball being slightly smaller, may leak at shallow depths but then seal with
pressure behind it.
Some time ago I suggested using a valve & looked at items such as this
http://www.stoneleigh-eng.com/duplex_ball_valve.html
that could be pulled apart easily & were thin sectioned to enable greater angle of movement.
My idea at the time was to use the existing ball but turn it, & drill out it's stem hole to fit the cue. But this would be great if the cue ball fits. There are a myriad of valves out there. If you found one that could be easily attached to the hull & just bolted together with the machined cue ball
in it, that would make it easier to emulate.
Have a look at this Wiki article. Pool balls / billiard balls differ in size & you may find a match
up between a ball & a valve.
http://en.m.wikipedia.org/wiki/Billiard_ball
Alan

Sent from my iPad

> On 28/11/2014, at 2:35 am, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> e 
> I have made a big discovery. A cue ball arm can be made very easily with a 1 1/4 ss ball valve and a 1 1/8 dia cue ball.  I removed the ss ball from the valve, just to check it out and found the ball is .004 in smaller than the cue ball.  I am going to assemble the valve with the cue ball in it and pressure test it.  If it works, I will machine the valve ends so the cue ball arm has maximum range of motion.  
> To build a duplicate cue ball arm like Gamma has requires some extremely technical machining.  When I removed the insert that carries the cue ball, from the hull, I found it was damaged and causes the cue ball to drag causing damage to the ball.  Since I do not have the skills and equipment to machine that part with the radius in it, I will try the valve idea.
> Hank
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