I know this is late but I just red your post.
1) Mark two lines around your shaft with a dark pencil . One at 4' and one at 8"
2) With a small plane set at a very fine setting ( paper thin ), start at the 4" line take off a shaving all the way down the shaft. Turn the shaft just enough to remove the pencil mark and take off another shaving. Continue till all of the 4" line is removed. Now go up to the 8" line and do the same thing. Don't stop till your plane goes off the shaft.
3) Sand and admire your work.
It doesn't take long to do a shaft once you get the hang of it.
