Springs

While helping out at a scouting event, planting trees, I ran across metal straps used to hold bundles of stakes together.  They seemed springy, and likely steel, so I thought, "spring steel!"  Well, they're not, but they did give me the opportunity to try to make spiral springs.  Here's one of the straps:

I started by annealing the strap, bit-by-bit in the flame of the blowtorch.  Then, I wound the spring with needlenose pliers.  In the picture below, one end of the spring is gripped in the vice while the other is in the pliers.  As the pliers are turned, the spring tightens.

It was initially quite kinked, so I wound the spring very tight to ensure even, round coils.  Since it was annealed, the spring seemed to basically stay put.  I then held the whole spring in the flame -- which mostly worked since the spring was small -- and brought it to bright red hot.

Unfortunately, I had a lot of trouble keeping heat on the outer coil, so it didn't get as hot.  In any event, when I was satisfied with the temperature, I quenched the spring in a can of water.

It took quite a bit longer to cool than I expected, so I stirred the spring in the water to ensure even cooling.  Here's the finished spring.

It's clearly uneven and imperfect.  I also forgot to drill any mounting holes, but I was also unsure of how it would turn out.  However, the spring rings when plucked, and moves pretty easily.

It seemed that when I pulled the spring very tight before quenching, the spring's shape was better.  However, the coils rubbed against one another (oil helped a bit).  That's why I ended up with the looser shape shown above.  It seems like the spring can take about half a turn in either direction without taking a bend that sets, which is pretty good given the fact that this is just some steel strap I found.