Certainly not a new idea, but in case you haven’t seen it here’s a trick for locating multiple threaded holes.
I needed to put some end plates on a slide bearing for the Z-axis of my CNC router. The plates would hold thrust bearings for the leadscrew, and provide a place to mount the motor and limit switches. I drilled and tapped the holes so long ago I’d forgotten what the dimensions were. (See my coming project page for this CNC project to get an idea of how long I’ve been working on it!)
It turned out to be quicker to make my own transfer screws than try measuring and aligning by sight. I simply tightened nuts on some pieces of threaded rod, chucked them in the lathe, and turned a taper on each one.
I held the plate in alignment and tapped with a hammer. Voila…