
The shaft is cut! My goal of rolling under electric power by the end of the month is now slightly less outrageous.
An observant reader will see a remnant of the old spline visible for 3/4 of the new spline. This is because the old spline was just a little bit too small to cleanly cut the new spline. I'm told this won't be a significant problem because the spline is so deep (3mm according to the drawings) and the torque isn't unreasonable. I'm likely to cut some of the shaft off to get the motor deep enough into the bell housing so this may make it even less of an issue.
The spark erosion machine left an interesting speckled finish to the spline. Less visible in the pictures are what look like marks from turning the outside in a lathe.