Source for springs?

[OPBN]

I will probably google it and look around, but was curious in the meantime if anyone knew of a good source for springs? I'm not looking for marker specific springs, just a general source for them. As an example of what I am looking for is a softer spring to replace the one on a pump kit I have. I recently came across an XM15 pump kit that someone had replaced the spring on and it was considerably lighter than the stock spring. I meant to swap it off onto the other kit I had, but forgot and now I would like to find one. Any thoughts?

Also, is there an easy way to measure spring pressure? I had thought about turning my scale on, putting the spring on it and pushing, but not sure exactly how to measure it...? Anyone have an easy way to do this?

[GoatBoy]

F=kx

There's only three variables to work with...

[OPBN]

F=kx

There's only three variables to work with...

Talk to me like I have no idea what you are talking about. I'm 46 and the only math my job includes is figuring out how to add markups to costs.

[luke]

http://www.dummies.com/how-to/content/how-to-calculate-a-spring-constant-using-hookes-la.html

[GoatBoy]

The last time I dealt with springs, the manufacturer basically wanted some physical dimensions of the springs, and the "k" constant.

F is force, and X is distance. So... fix one, measure the other.

So, as a layman, I once did this for a T8 magazine, where "X" was actually in known units of paintballs.

https://spreadsheets.google.com/pub?key=0AtUb05cFvbYmdHlRME1oR2I3SnlnUmpNVmlFcF9EMFE&hl=en&single=true&gid=0&output=html

Other way to do it would be to take an object of known weight and put it on the spring and just measure the displacement.

[lobo_fuerte]

Your local hardwood store will have many springs, I was just at an OSH were I live and they have many with different sizes tensions and widths.

[Spider-TW]

Home depot has some assortments, but for longer than an inch or so, you may have to pick out singles on a rack.

Measuring the deflection from a known weight (or a volume of water) as goat boy suggested will tell you about any one spring.

The k factor is designed on the diameter of the wire, the diameter of the spring, the number of turns, and the overall length. The way the ends are done has a little effect as well.

Generally, smaller wire diameter, larger spring diameter, and higher pitch (number of turns per length) will each lower the spring constant, if all else is equal. If you have a starting spring you can go to McMaster. Com and try to make changes, usually in pitch or wire diameter.