Originally Posted by
Cassave
Of course there's no need to make a constant radius block, or bend a constant radius curve in the blade. I made my bender with a block with an involute profile. An involute curve is a decreasing radius curve used on gear teeth. It's technically the path traced by a point on the circumference of a circle as the circle is rolled along a plane (for gear teeth that's important since there's no sliding contact) and incidentally it's a very "pretty" curve.
Cassave; Looked like a classic "French Curve" and maybe it is... But a quick Boogle to site below provides a layman's drawing and a simple step by step on how to draw one without any match beyond simple addition. Should be a "small brainer" to sketch one out on the side of the wood or metal slab one wants to make a bender from. Thanks for the correct name/term.
http://www.google.com/imgres?imgurl=...ed=0CCcQ9QEwAw
/k