erdix, also known as Talus or Calus. A Greek mythological figure, the nephew of Daedalus a skilled craftsman. Perdix apprenticed to Daedalus and under his tutelage was credited with the invention of the first saw fashioned from the backbone of a fish. He also attached two branches of metal together with a rivet on one end and sharp points on the business end to craft the first pair of dividers.
Daedalus burned with jealousy at his inventive nephew and pushed him off a towering cliff. Athena came to the young inventors rescue and turned him into a partridge before his body was dashed against the rocks below.
Grey Partridge (Perdix – perdix)
Which is why we will never know the secret behind the saw nib.
Design Matters 
Maybe the nib represents the chip on Daedalus’s shoulder.
The new book has reopened my eyes to the usefulness of the divider.
Thanks for that.
Mark,
You may have hit on the best explanation ever!
George
I laughed at the saw nib line. 🙂