Wal, it’s always nice to see people coming up with new innovative products that offer a solution to a problem. I look forward to seeing the new designs if you will be sharing them here as well.

The only thing I can’t see you've covered is how you will align the base unit over the location to be drilled/tapped. I’m thinking a rod made of clear plastic, bored out to almost all the way with a small center cross or a marking in the center of what would then be a tube with an end to it may work well, though I’m now thinking “but how well would you be able to see down the tube to place the mark/crosshair, L.E.D illumination built into the plastic tube?

What do you think, have you got something else in mind?

.Me