Many thanks to Glen for posting this, very informative for new guys just getting into str8 razors.
The first time I needed to breadknife a razor was to remove a frown and used the 90 degree method. After removing the frown I proceeded to rest the bevel and thought I would never get it set. After a lot of stokes, a lot of time and some cussing I finally got the bevel set, moved up the progression and ended up with a very nice shaving razor.
A couple of years later I found a video of a fellow taking out a chip and started breadknifing at about a 45 degree angle and it didn't take long for him to remove the chip. The next time I had a chip to remove I used this method and it really shortened the time it took to remove the chip, set the bevel and finish honing the razor due to not having to remove as much metal using this method.
This method also allowed my to take a second look at chipped razors that I would not even have considered before.