GTA
General Discussion To Gateway To Airguns => The Shop => : gunsup0331 August 24, 2008, 05:47:06 AM
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To combat the twisting action associated with springers, would it make sense to round off the front of the tophat so it rotates against the inside of the piston? I know it would spin a lot easier than lubed/compressed washers would. Any thoughts?
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icant add an attachment what is another way to do a picture, i know for a fact my little Paint drawing isnt bigger than 150k
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I think I can picture what you're talking about. I believe that if the flat face of the tophat (that rides on the inside of the piston) were Domed, then it would lead to spring cant as it would allow the spring to bow to one side or another once cocked.
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I had thought about that as well, my tophat fits well enough in my piston to make a VERY slight rounding of the front of the tophat a non-issue as far as spring cant, besides, its not like the tophat goes anywhere, lol.
BTW my picture is like, 1.5"x2.5" in MS Paint, dont get much smaller than that
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I would assume that you are referring to torque or axis rotation. Yes, even the slightest rounding will lead to not only spring cant especially if the spring is not cut perfectly square and flat on the end but it will also cause more spring vibration as well as harmonics and is the reason that manufactures do not do it. It would be expensive to cut and finish a spring to those tolerances. In addition, it might even allow the spring to "spin and that too could create other problems, like wear on the spring block.
Most pistons do not allow for much for spring clearance and it wouldn't take much to reduce the clearance enough to bring it even closer to the piston wall causing other problems. Besides, it is much easier to make a simple thrust washer and far more efficient.
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Thanks for the words of wisdom Bob!
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Hi.... What I have done to my Geox to try and releave the twisting motion.
I put a 3mm deep hole in the top hat with a 6mm round end mill cutter & the same in the piston
but only 2mm deep so that a 6mm ball bearring could sit in there .
doing this wil remove some of the surface area in contact so it will let the spring twist with out
transfering the touque though the piston and into the chamber body. I was concerned
about the pin point load that the spring can apply to the piston but 500 plus pellets
its still going strong "fingers crossed" but I can't say it has made a big differents.
On some guns it may be possable to do this at both end of the spring.
Letting the spring and guides float
kiwi
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Cool idea kiwi. Any thoughts on the spring canting effect this may have?
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Hi... My idea was that you cant stop the spring torque " so doing this will hopfuly rejuce the efect on other componets ie..piston/chamber less mass trying to move.
I have done it to my Geox 1.77 but havn't noticed any mauger change but then the change would only be small.
kiwi
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which brings me back to the original question...if its gonna cant, why not have it spin, too?
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When cocked, how much room would you say there is between the back of the tophat and the front of the guide on the Cros. B19's?
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Top hat should not be tight in the piston in the first place. A washer in the end of the piston gives it a smooth surface to rotate on. Have you looked down in the piston? it is usually a rough finish that will hang up a tophat, more so a synthetic one.
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yeah i tried to smooth it out but lack of proper tolling left it with ridges (slightly polished ridges however...)
When i "tuned" my gun i put the washers on the tophat, should i have put one in front of the tophat instead/as well? Not like it could go anywhere...
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The washer should be between the tophat and the front of the piston. That wayt the whole spring, tophat assembly can rotate. make sure the washer is free to spin in the piston, not tight. and polish that sucker good!