Piano Wire, Spring Steel

[flmason]

Can anyone point me to good info on "piano wire" or spring steel?

I'm curious what materials are commonly available, and what's involved in making springs, since they are at the heart of most gun designs in one way or another.

That said, other than the Richardson Guerilla Gun, anyone know of any gun designs that don't rely on springs?

[mrbigtexan]

wouldnt all guns have to have a firing pin or hammer spring?

[keith44]

Can anyone point me to good info on "piano wire" or spring steel?

I'm curious what materials are commonly available, and what's involved in making springs, since they are at the heart of most gun designs in one way or another.

That said, other than the Richardson Guerilla Gun, anyone know of any gun designs that don't rely on springs?

Water pistols, oops nope they have a "trigger" spring, hmm...


Brownells has a good selection of spring stock kits

[tacklebury]

I believe there is an inertia controlled firing mechanism, but I haven't seen it in a long while.  Had some kind of eliptical, but you had to pull the trigger pretty fast to get it to fire, so accuracy suffered.

[flmason]

wouldnt all guns have to have a firing pin or hammer spring?

Google "Richardson Guerrilla Gun"... basic answer is "Nope".

http://www.youtube.com/watch?v=xt3NuCbxSQQ

or simpler yet...

http://www.youtube.com/watch?v=w_KfHLlSnQc

But not exactly "target arms", LOL!

[flmason]

Can anyone point me to good info on "piano wire" or spring steel?

I'm curious what materials are commonly available, and what's involved in making springs, since they are at the heart of most gun designs in one way or another.

That said, other than the Richardson Guerilla Gun, anyone know of any gun designs that don't rely on springs?

Water pistols, oops nope they have a "trigger" spring, hmm...


Brownells has a good selection of spring stock kits

Thanks much, didn't realize that.

Was also hoping to obtain materials from more ubiquitous sources. Basically trying to be tied to any given supplier.

[Bigeasy]

Designs like the Remington 700 electric fired rifle can substantially reduce the number of springs in a gun, especially if a pressure sensor is used on the trigger as opposed to a trigger spring.
 
Larry.

[flmason]

Does anyone know anything about how to predict the characteristics of the final spring? Things like how much force it can store, etc.?

Kinda trying to figure out... if one were to buy a spool of music wire or the like... what is the right thing to ask for?

I realize it's a potentially expansive topic though.

[keith44]

I don't have all the details, but assuming a spring wire is always made of the same steel, and hardened to the same BHN (which is almost never the case)


Then the larger diameter the wire the stiffer the spring will be, the tighter the coil is wound (diameter of coil) the stiffer it will be, and the greater the number of turns per inch the stiffer it will be.

[oldred]

Does anyone know anything about how to predict the characteristics of the final spring? Things like how much force it can store, etc.?

Kinda trying to figure out... if one were to buy a spool of music wire or the like... what is the right thing to ask for?

I realize it's a potentially expansive topic though.

Music wire is available in many different sizes and is easily wound into about any spring type you need, push or pull coil springs or what I refer to as "mouse trap" springs. In the Highwall replica I built I used .055 music wire for the main spring like Winchester did in the later models and another small piece in the "mouse trap" configuration for the sear spring, this replaced a flat spring like the originals used. Music wire is available from just about any machine shop supply source and it is easily found on E-Bay in just about any size you need. For flat springs these same sources have spring steel in many thicknesses but usually a flat spring must be custom made for the task and this will involve annealing the material to make it soft enough to work and then re-tempering when finished, neither is hard to do. I have a flat wound spring that I took from a junk car door that was used for the window mechanism and this coil of flat material has been used to make several firearm springs, I just cut off the length I need then heat it red hot, let it cool slowly then shape/drill/grind or whatever is needed then re-temper it.

To anneal a spring and make it soft is easy, just heat it red hot and bury it in dry sand so that it will cool slowly-the slower the better! After it has been annealed and shaped into the desired shape it must be re-hardened and tempered and while this is a bit more complicated it's still not too hard for the home shop. Re-heat the spring to a cherry red then immediately quench in cold water, this will return the spring to it's former hardness (or close) but will leave it VERY brittle and surprisingly easy to break so it must be tempered to restore it's toughness. This can be accomplished by several means but the easiest is is to just stick it into a toaster oven set on 400 deg for about 45 minutes, this usually does the trick.

[mechanic]

Any good hardware will have spring assortments in various sizes and strengths.  These can be cut down if needed. 
 
Ben

[flmason]

Does anyone know anything about how to predict the characteristics of the final spring? Things like how much force it can store, etc.?

Kinda trying to figure out... if one were to buy a spool of music wire or the like... what is the right thing to ask for?

I realize it's a potentially expansive topic though.

Music wire is available in many different sizes and is easily wound into about any spring type you need, push or pull coil springs or what I refer to as "mouse trap" springs. In the Highwall replica I built I used .055 music wire for the main spring like Winchester did in the later models and another small piece in the "mouse trap" configuration for the sear spring, this replaced a flat spring like the originals used. Music wire is available from just about any machine shop supply source and it is easily found on E-Bay in just about any size you need. For flat springs these same sources have spring steel in many thicknesses but usually a flat spring must be custom made for the task and this will involve annealing the material to make it soft enough to work and then re-tempering when finished, neither is hard to do. I have a flat wound spring that I took from a junk car door that was used for the window mechanism and this coil of flat material has been used to make several firearm springs, I just cut off the length I need then heat it red hot, let it cool slowly then shape/drill/grind or whatever is needed then re-temper it.

To anneal a spring and make it soft is easy, just heat it red hot and bury it in dry sand so that it will cool slowly-the slower the better! After it has been annealed and shaped into the desired shape it must be re-hardened and tempered and while this is a bit more complicated it's still not too hard for the home shop. Re-heat the spring to a cherry red then immediately quench in cold water, this will return the spring to it's former hardness (or close) but will leave it VERY brittle and surprisingly easy to break so it must be tempered to restore it's toughness. This can be accomplished by several means but the easiest is is to just stick it into a toaster oven set on 400 deg for about 45 minutes, this usually does the trick.

Thanks for the details on heat treating. The toaster over part is interesting. Never have owned one, LOL! Guess now I have an excuse.

Just let it air cool after the toaster... or just let the whole over cool down. Clearly "speed of cooling" is a huge factor here.

[gunnut69]

After tempering the spring in the oven it can be quenced as before. If the cooling is allowed to be slow it will soften the spring action.

[oldred]

An old blacksmith trick, but messy, to temper the hardened spring was to place it in a small metal pan and then pour in enough oil (used motor oil is perfect) to just cover the spring and then set the oil on fire, just as the oil starts to burn out remove the spring and quench it. I strongly disagreed with doing this and explained to the guy who described the method to me that the burning oil would get the spring much too hot but after seeing him successfully do several springs and learning that this trick has been done for years I have to now admit it works pretty good! Depending on the alloy the spring is made of the finial step of quenching may leave the spring too hard so some alloys are better left to air cool, this is trial and error but it's best to air cool first then if the spring is too soft re-harden and try again-better all around to just use the toaster oven however.


Either of these methods works ok for flat springs but I would never attempt to heat treat a part like a hammer or sear in this manner, heat treating action parts requires a proper controlled heat source for both hardening and tempering.

[dave22250]

Grangers, they sell piano wire usaully in 1 lb and 3 lb spools in a lot of diff. thicknesses