If, like me, your grinder is the basic sort with a flimsy fixed rest you may find it very difficult to produce a perfectly square smooth bevel on your chisels. They will be fine for the average work of paring if the edge is honed. For mortice chisels however that are designed to be self-jigging anything less that absolutely square will cause twisting and leading and the horrible leaning mortice that is wider than the chisel. My solution may sound like a counsel of despair. File your bevel. In a couple of minutes you will get a perfectly square even slope right to the tip. Raise the tip on the oil stone to create a slight secondary bevel. Use a straight lath clamped to the side of your stile to sight your chisel. Chop. No steering required.