[john walker's workshop]

the bottom cut doesn't make much difference if it's 60 or 75. if you use a stone, the 75 tends to wedge. i use a 60° hand cutter so i can remove metal where i want instead of where the stone wants. a lot of times when you do the final lower cut, there is perfect seat width on one side and too wide on the other. the stone tends to follow the hole and remove material from the perfect side while grinding on the wide side. a single blade hand cutter doesn't do that.