Step 1: What you need
You can get windshield wipers from free in a scrapyard. Wiper blades contain 2 stainless steel strips that are very flexible.
Step 2: Bending the strip
Bend the strip to a "U" shape and cut it to the lenght you choose.
Start making a small circle on the other end, but do not close it, leave enough space to insert the iron wire.
Step 3: The iron oval
Insert the circle of the strip in the shorter end of the wire to determine where to cut it.
Bend the wire to a half oval shape on one side and draw it near the pivot's end.
Do the same on the opposite side and cut to measure.
Step 4: Assembly
Squeeze the circle to close it on the pivot.
Bend the oval to the right curve and refine the shape of the steel strip.
To see more: www.pennabilli.org