I'd be grateful for any tips for ensuring that a hole made with a hand-held drill is accurately at 90 degrees to a surface. I've wondered about knocking up a flat metal plate with a short stub of tubing set exactly perpendicular to it and using that as a guide, but it would be necessary to make a whole set of them for different size bits. It would also, in smaller sizes, be very tricky to position the tube exactly where the hole is to be drilled/
I've tried an accurately-cut V shape in a thick block of wood and placing the drill into the corner of the cutout; this has worked up to a point but I wonder if something more spot-on might be possible.
Many thanks.