I am building a credenza using knife mortises which require shallow mortises near the edge (only 1/8"). All the sites I found mention doing it with a router - which is what I ended up doing after a few practice runs with a chisel led to blowing out edges. I had pre-scored the mortise edges and then slowly deepened with the small chisel, but this along wasn't enough.
Just go even slower and more delicately? So special tricks to doing this kind of work by hanbd?