What to make a gib key out of

[Ed: Wondering what a gib key is? It is the metal tongue which retains the flywheel onto the crank shaft. Slightly L shaped it is jammed into the keyway (a groove cut into both the flywheel and crankshaft and lined up to match each other). It has two jobs the square part of the key stops the flywheel from rotating independantly of the crankshaft, and the key is tapered so it is thicker towards the outside (or bottom of the L) which stops the flywheel drifting off the shaft (or further on for that matter). It does the same job many engineers use a set screw for these days - the gib key is still used when there is a lot of moving mass as a set screw cannot handle it.]