Thursday, March 30, 2017

DIY Metal Coil Springs

Make Your Own Springs
I needed a spring, but wanted a custom size and shape. I made my own extension and compression springs.

I remembered making coils of wire when I made chain mail.
I used the same concept to create a smaller jig. The wire I used is 22 gauge. This concept works for various sizes of wire, but larger wire can exert a greater force when coiled. Be very careful when you cut the wire, it can uncoil and hit your hand. Smaller wire won't hurt, but larger wire can injure you.

Supplies
  • Wire for the spring, I used 22 gauge
  • Metal rod, I used 3/16"
  • 36" long 2x4 to create the jig
  • (4) 2" screws for the jig
  • Steel wool & aluminum foil for heat treating
 Tools
  • Drill & 1/16" bit
  • Bar clamps for building the jig
  • File to create a notch in the metal rod for drilling
  • Rasp
  • Pliers
  • Wire cutters
  • Metal bar stock compression spring spacer, I used 1/8" stock
  • Toaster oven for heat treating 
Create the Jig
Wood 2x4 jig, 24" long
I built a jig out of a scrap 2x4. It's 24" long with 6" uprights. I clamped the uprights together when I drilled the metal rod center hole so that my hole is centered in both. If you don't center the hole, you'll have to use a rasp so that the metal rod will line up with both uprights.It must spin freely.
Screw the uprights to the base. A two foot long jig is a good length that gives you plenty of room, but you can certainly make it shorter.
File a notch in the bar and drill a 1/16" hole
Use a metal file to create a notch in the metal rod. Then drill a hole larger than your wire through the rod.

Create the Coils
Thread one end of the wire through the hole in the rod  and attached a drill to the other end of the metal rod. This setup creates the coils.
I'm using 22 gauge wire
Go VERY slow, one hand feeding the wire, the other on the drill. I went very slow to ensure I created nice tight coils. It takes a couple tries to get the hang of it.
You want to feed the wire slightly behind the coils on the rod if making an extension spring. The slower you go, the easier it is to line everything up. If you align the wire too far behind the coils, it will jump the existing coil. Reverse direction on the drill to try and save the coil.
Go very slowly as you coil the wire
Once the spring is long enough, clip the wire BUT watch for recoil
Once the coil is long enough, snip the end of the wire. The wire will uncoil so if you're using a thicker gauge, be careful.
Use bar stock for as a compression spring spacer
To create a compression spring, use steel bar stock or something else with a square edge to act as a spacer as you coil the wire. With bar stock it's easier to create coils as the wire is less likely to cross up with the height of the bar stock.
Put the spring in steel wool and the steel wool in aluminum foil
Heat the springs for 1 hour at 400*
The coils weren't springy enough, and I was afraid they would lose their shape in use.
A little bit of googling suggested I heat the spring. I made a pocket for the spring in steel wool, wrapped the steel wool pocket in aluminum foil, and then heated it in my toaster oven. My thought is the steel wool and aluminum will help trap the heat and bake the springs better.
The maximum temperature of my toaster oven is 400*, and I did that for 1 hour. I also tried 2 hours but didn't notice a difference in the spring.
Heating the spring did the trick. The springs felt stronger, and didn't seem like they would lose shape as easily.

You can also create a stop for an extension spring so that you don't overextend it and stretch the coils.
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