This is not a hammer debounce device

This is not a hammer debounce device

Joined: December 14th, 2010, 5:08 am

June 11th, 2012, 4:27 pm #1

because the hammer still bounces, just not against the stem

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i cut off about 4.5 coils from a 1377 valve spring and glued it to a washer/rivet thingy. using double sided tape i stuck it to the outside of the valve. the theory was to absorb most of the hammers energy before it even touched the stem and it seems to work. now it just taps the stem and my valve retains quite a bit of air.

i get two decent shots. the first one being the most powerful and the second shot loses about 200-230 fps. then i have to actually dry fire it TWICE to get the remaining air out. now i just need to get a lighter hammer and figure out a way to make a spring adjuster for it

let me hear what you guys think. I know some of you are very well educated in the physics of this type of stuff. i think it could be improved a bit

oh btw i switched hammer springs too. i used a 2240 spring


DNADNNOID
Last edited by Dnadnnoid on May 12th, 2013, 4:32 pm, edited 1 time in total.
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Joined: November 28th, 2002, 6:26 pm

June 11th, 2012, 4:39 pm #2

I'm sure you're right that your spring buffer accepts a lot of the hammer's energy and prevents it from making it to the valve stem. But then it gives that energy back to the hammer in the form of a more violent bounce.

So my question would be, what prevents that added bounce energy from rebounding from the hammer spring, then driving the hammer back to compress the buffer spring and hitting the stem again?

Steve
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Joined: December 14th, 2010, 5:08 am

June 11th, 2012, 4:41 pm #3

because the top of the spring sits far enough away from the stem that any bouncing that occures doesn't transfer onto the stem. you should try it
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Joined: December 14th, 2010, 5:08 am

June 11th, 2012, 4:45 pm #4

the 1377 valve spring is very stiff!
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Joined: November 28th, 2002, 6:26 pm

June 11th, 2012, 5:09 pm #5

Eventually I understood why they don't - and can't - work very well.

Steve
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Joined: December 14th, 2010, 5:08 am

June 11th, 2012, 5:15 pm #6

instead of being all smug about the fact you did it first
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Joined: November 28th, 2002, 6:26 pm

June 11th, 2012, 5:22 pm #7

...essentially exactly the same in effect as reducing the energy of the hammer strike by any other means - e.g., by reducing the rate or preload of the hammer spring.

To get useful hammer debouncing, I found that you always need to provide somewhere for the energy of the hammer's rebound to be dissipated permanently - not just temporarily stored. Springs can't do that.

Steve
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Joined: March 1st, 2002, 12:22 am

June 11th, 2012, 6:25 pm #8


and thats done thru the friction the HDD causes?

hmmm hadnt thought of it in those terms.....


dr_subsonic's pneumatic research lab

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Joined: November 28th, 2002, 6:26 pm

June 11th, 2012, 6:32 pm #9



Steve
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Joined: March 1st, 2002, 12:22 am

June 11th, 2012, 6:34 pm #10

got _something_ right today

dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic
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