To drill hole on a new skin to match an existing hole on the structure underneath, for repair or new construction work, one can use paper or clear acetate sheet for template. But a rivet hole finder works faster and in most case, more precise.

For budget builders and all handyman type, there is a simple way to make this tool yourself: Brazing a cut-off head of a nail to the hole at the hack saw blade end (see photos) and brazing the second broken blade on top of it. The nail finds the rivet hole, and the hole on the second blade makes a drill guide

I found out that holes on the saw blade are ALMOST 5/32", i.e.bigger than A 4 rivets and almost as big as A 5. So, for accurate drilling, I use an extra piece of scrap steel and drill a 1/8" hole at one end of it, to make for the drill guide. Brazing a nail head to the center of a bigger hole need some care. Masking tape or electrical tape over saw teeth saves aircraft skin and yours from cuts and scratches. After some use, the shallow drill hole on the nail head improves its ease of use, that you don't have to finish the hole with this rivet hole finder removed as in the beginning.

My examples look scrappy but work quite well.

Happy Home-building!