The choice of metal for making a compression spring depends on several factors including the required strength, durability, corrosion resistance, and the environment in which the spring will operate. Here are some of the most commonly used metals for compression springs:

Music Wire (ASTM A228)

• Pros: High tensile strength, good fatigue resistance, relatively low cost.

• Cons: Susceptible to corrosion, not ideal for high or low temperature environments.

• Best for: General applications where corrosion isn't a major concern, like in toys, automotive parts under normal conditions.

Stainless Steel (e.g., 302, 304, 316):

• Pros: Excellent corrosion resistance, good tensile strength, suitable for a wide range of temperatures.

• Cons: Lower fatigue life compared to music wire, more expensive.

• Best for: Outdoor or harsh environments, food processing equipment, medical devices.

Oil Tempered Wire (ASTM A229):

• Pros: Higher fatigue life than music wire due to tempering, good for slightly higher temperatures.

• Cons: Not as corrosion-resistant, more brittle.

• Best for: Automotive suspension systems, heavy machinery.

Chromium Silicon (ASTM A401):

• Pros: High tensile strength, good for high temperatures up to about 475°F (245°C).

• Cons: Expensive, less corrosion resistant than stainless steel.

• Best for: High-temperature applications, like in engines or exhaust systems.

Chromium Vanadium (ASTM A232):

• Pros: Excellent fatigue resistance, good strength, can handle higher temperatures than music wire.

• Cons: More expensive than music wire, not as corrosion-resistant as stainless steel.

• Best for: Shock absorbers, heavy-duty applications where high fatigue resistance is needed.

Phosphor Bronze or Beryllium Copper:

• Pros: Non-magnetic, excellent electrical conductivity, corrosion resistant.

• Cons: Lower strength, more expensive.

• Best for: Electronic applications, marine environments where electrical conductivity is needed.

For most general applications, music wire is often the best choice due to its balance of cost and performance. However, if the spring is going to be exposed to corrosive elements, stainless steel would be more appropriate. If high temperatures or extreme fatigue demands are involved, you might lean towards chromium silicon or chromium vanadium.

The best size of music wire for making a gun compression spring depends on several factors including the specific firearm, the spring's required force, its length, and the space constraints within the gun. Here are some general guidelines based on common practices:

For Pistol Magazine Springs:

• Typically, music wire with a diameter around 0.045" to 0.060" (1.14 mm to 1.52 mm) is used. For example, a Glock magazine spring might use around 0.060" (1.5 mm) wire diameter.

For Rifle Magazine Springs:

• These might require slightly thicker wire, often around 0.060" to 0.075" (1.52 mm to 1.9 mm) or more, depending on the magazine size and the type of rifle.

For Other Gun Components like Trigger Springs or Plunger Springs:

• Smaller diameters might be used, typically in the range of 0.020" to 0.045" (0.5 mm to 1.14 mm), depending on the specific part and the force required.

For our example we are using Precision Brand music wire in various thicknesses depending on the application. Here is a couple of good options:

You can find more information about the product and sizes here: https://www.precisionbrand.com/product- ... usic-wire/

To make a compression spring jig using a long bolt/screw and two coupling nuts, where one nut is cut and drilled to accept music wire, you can follow these steps:

Gather Materials:

• A long bolt or screw (long enough to accommodate the length of the spring you're making).

• Two coupling nuts of a size that fits the bolt.

• Music wire for the spring.

• A drill with appropriate drill bits for the wire size.

• Cutting tools (e.g., hacksaw, angle grinder, or Dremel for cutting metal).

• Vice or clamp for holding the nuts securely while working.

• Safety gear (gloves, goggles).

Prepare the Coupling Nuts:

• Cut One Nut: Take one of the coupling nuts and cut it lengthwise. This can be done with a hacksaw, ensuring you cut just enough to open it up but keep the threads intact for the bolt. You want to create a sort of 'C' shape where the nut can still thread onto the bolt but has an opening for wire insertion.

• Drill the Cut Nut: After cutting, drill a hole at one end of the cut nut. This hole should be slightly larger than the diameter of your music wire. It should be positioned near where the cut opens, allowing the wire to pass through but still be guided by the nut when wrapping around the bolt.

Assemble the Jig:

• Thread the long bolt through the uncut coupling nut, positioning it towards one end of the bolt. This nut will act as a fixed point for the spring's start.

• Thread the cut and drilled nut onto the bolt, ensuring the drilled hole is accessible for wire insertion. This nut will be adjustable along the bolt to control the length of the spring.

Winding the Spring:

• Secure one end of the music wire through the hole in the cut nut, ensuring it's held firmly but can still slide as you wind.

• Begin rotating the bolt or screw (you can do this manually or with a drill if the bolt is mounted in a drill chuck). The wire should start wrapping around the bolt, with the cut nut guiding the wire and maintaining tension.

• As you wind, adjust the cut nut along the bolt to control the spacing between the coils. You might need to manually manage the tension to ensure the coils are evenly spaced.

Finishing the Spring:

• Once you've wound the spring to the desired length, stop winding.

• Carefully remove the spring from the bolt by either unscrewing the bolt or sliding the spring off if possible.

• Trim any excess wire, ensuring the ends are cut cleanly.

• Optionally, you might want to perform stress-relieving on the spring to remove any residual stresses from the winding process. This could involve heating in an oven at a controlled temperature as suggested by various guides online.

Safety and Precision:

• Always wear protective gear, especially when cutting or drilling metal.

• Ensure the jig setup is stable to prevent any accidents with the rotating bolt or wire.