spring for a 400psi PCP?

[ilovefire]

i am currently attempting to make a low powered PCP air gun and am stuck on what spring i need and where i can get it

the hammer valve seat diameter is 10mm
pressure when full 400psi
hammer weight 60g
hammer length 4.5cm
distance between valve and back of hammer tube 12.5cm
OD of the spring needed 13mm

with all that in mind is there anyone here who is smart enough to figure out what spring i need? and where i could get said spring? also if it helps i have tested dropping the hammer down a 65cm tube onto the the valve and got to open the valve almost to just the right amount. if someone can help i may possibly have an alright gun to show you guys sometime soon, and if you like i can post pics of what i have so far, but ill have to wait for the internet to go back to full speed
cheers

[jackssmirkingrevenge]

read up http://home.earthlink.net/~bazillion/intro.html

[Lockednloaded]

Im not great with spring calculations, but Hooke's Law may be of intrest if you hadnt considered it

[Crna Legija]

i am currently attempting to make a low powered PCP air gun and am stuck on what spring i need and where i can get it

the hammer valve seat diameter is 10mm
pressure when full 400psi
hammer weight 60g
hammer length 4.5cm
distance between valve and back of hammer tube 12.5cm
OD of the spring needed 13mm

with all that in mind is there anyone here who is smart enough to figure out what spring i need? and where i could get said spring? also if it helps i have tested dropping the hammer down a 65cm tube onto the the valve and got to open the valve almost to just the right amount. if someone can help i may possibly have an alright gun to show you guys sometime soon, and if you like i can post pics of what i have so far, but ill have to wait for the internet to go back to full speed
cheers

have you checked bunnings they have a spring isle.

[ilovefire]

JSR

thanks, altho i must admit to not reading it the whole way through because must of the instructions were for people with lathes, talking about lathes congratulations on getting yours
i did however attempt making a spring from what i could understand of it, and it kinda worked, i mean it was a spring, but it didn't like being compressed in the tube and kept getting jammed, it is now located in the bin

Lockednloaded

that link just confirmed what i already knew about springs

Crna Legija

yes i went to bunnings but they didn't have the right diameter, and are bloody expensive (at least for some who works for $20 a day)