Grinding belt makes concave edge at the heel

[SHARPCO]

There are two ways I try to overcome this. First, I don't initiate contact at the heel. I start well in front of the heel and go to the point, then without losing contact, reverse from the tip to the starting point. You don't have to worry about getting all the way to the heel until the rest of the edge is done. You will always have better control at the heel if you end your pass at the heel. It's so much easier to control your contact area and pressure that way, pressure being the most important thing of all.

Thanks Mark, 

I wonder what the second way is.