On Monday, January 15, 2018 at 6:25:43 PM UTC-5, -MIKE- wrote:

Next time, I may put flip-stops on the fence to make it even more full
proof.


That's how the Blum hinge boring machines work - they have flip stops. But for odd sized doors or one-off cabinets I would install the plates first. I found that the ones we used sort of came to a point at the center. I'd then push the edge of the door against them in the opening with appropriate shim under the bottom. This left little indents that I'd then mark with a saddle square around to the back, which I'd then line up with the center line on the boring machine. Very quick, very accurate. I'm sure not all cup hinges have this - we used the Blum brand.

JP