Selection, splitting and staggering.

Straightening

Basic Beveling

mm fly rods

Heat treating

Hand planing 1
Hand planing 2

Gluing

Final dimensions

Attaching hardware

Wrapping

Finish

Rod sock and tube

Here's where the extra 3" on each end of the section comes in.  I check my dimensions by placing a small strip of tape every 5 inches on my  sawhorse, then I write the target size of the taper for each station..   Next I use dial calipers to check against the actual size against my target.  I move the section back and forth until the smallest size on the section lines up with the same size on workspace.  I use a small sanding block to bring any over sized portions of the section in line.
It's at this point that I cut the tip to length and cut the the butt to receive the female ferrule.  I start by coming up with the section length, which, (for a two piece rod) is 1/2 the length of the rod plus 1/2 the length of the ferrule tube.  Next I figure the length of the tip top minus the tip top barrel. I'll need to shorten the top section by that much.   All this will give me the total length of the top section.  I'll match the butt section to the top section's length. 
I now have a butt and a tip that are the correct size for the rod I'm building.  It's time to attach the hardware.