Got a good idea - I used this to drill holes in my transom and needed to know they were all at the same angle - you only want to drill a big hole once in a critical spot:
There is company named General - they sell inexpensive, eclectic tools. The tool I am referring to allows you make an exact angle hole w/ a drill. It attached to your drill chuck and has an aparatus..
SH*T it's hard to explain - hopefully this picture I copied shows up:
