Originally Posted by
WhiteTiger
Top rake makes a big difference, but the usual way of getting it is to grind more end relief on the blade and then set the cutting surface above center.
Mostly just a matter of economy, I suppose. Once you've sharpened away all upward curving end of the blade, you have to throw away (by grinding) all the rest of your notch length before you can sharpen again. If you grind the end relief and set above center, you never have to discard any length, just regrind the end of the blade.
It's also much simpler to do the end relief. I always just did mine by hand on an 8" bench grinder (the wheel arc is handy, as it leaves more support material closer to the cutting face).
Tiger