Some basic information on stress curves:

The X axis is rod length, with the tip on the left and the
handle on the right.

The Y axis is ounces per square inch. This sounds like
a pressure, as in psi, but it is really a stress measurement.
The square inch refers to the area of the cross section of
the rod at that point. 

The higher the stress curve goes, the more the rod will bend, 
taking the curve as a whole. I say this because a reading of 
200,000 near the tip, where the rod is thin in diameter is going 
to bend more than a reading of 200,000 near the handle where 
the bamboo is thicker. But, if you compare a whole stress curve 
of one rod to the whole stress curve of another rod, the rod with
a higher reading at the same point along the length will bend more
at that point.

A stress curve means nothing if you can't relate it to something.
The only way you can start to see how a stress curve can help
you is to graph up the stress curves of real rods and cast them.
In my case I didn't have a bunch of rods to try. I had to make
them. I now have a bunch of experimental rods lying around,
8 at last count. I was able to sell a few of the better experiments.
I was also lucky in accidentally making a rod I really like ( a 
Cattanach taper) on my third attempt, and being able to contrast 
that to a rod I really didn't like (a Garrison taper).

Three things I have found really help me in rod making. Being able
to split a culm to 32 strips top of the culm, 24 bottom of the culm.
Being able to sharpen my plane irons really sharp, and understanding
stress curves.

Darryl Hayashida

######