A cleaner picture. I think it's for a string instrument. Looks machine made.
Marking:
l47A = on the bottom?
70 , 7 , 3 = on the side. Maybe the notches are 4,5,6?
3 1/16" long, Circle is 3/4" diameter x 9/32 thick
http://"http://home.pipeline.com/~shootzf/brass-tool2.jpg