this has probably been done before but i'll post it anyway,i was building this evening and needed to cut a 1/2"x1/4" channel 6" long in some balsa,i do not have any wood chisels 1/2" wide so set to thinking how to do it,i got a piece of 1/2"x1/4" spruce,cut a chisel edge on it and used that instead,i was very pleased and surprised at the results i got,hope somebody finds it useful.