Fred,
Your Dad is absolutely right. Don't buy the jig.
I like the straight edge idea too, but for me I only use a combo. square off the edge of the door. The hinges have alot of flexibility in their assembly & focusing on just one hinge at a time is the important thing. I find that when I spread myself out to focus on the alignment of two or three hinges at once, I'm reaching across the whole door to hold it all & then reaching to each hinge to drill. By staying on top of each hinge, you'll have greater accuracy & speed. Remember, that door edge is ripped & then veneered, laminated, dressed & or sanded by the time you apply the hinges. It might not be exactly the straightedge that your steel straight edge is. Also, if dust got between the fence on the drill press & the door your holes will vary in distance from the door edge. All these things are minor & the euro hinges are designed to adjust so well in three directions that none of it matters. I feel if you try to place a steel straightedge against the cups on a long door with more than two hinges, the dead on straight edge will always only sit against two, or only the center cup. This negates the contact to the remaining hinges & can lead you to frustration over why this is.
Just remember, the fact that each hinge cup is square to the edge's adjacent 4-5", you'll always be fine.
Oh, & it's just woodwork, not a machinists shop. Nothing we deal with is perfectly square enough for them. I've never
seen a truly square corner to a room, yet I seen many stunned trim carpenters, who don't know how to scribe fit a cabinet or counter.
One more thing, don't use too large a fence on your drill press for the same reasons. You only want the contact at the edge by the hinge you're drilling on the drill press. If the door is sitting against high or low spots in other areas, it affects your spacing from the edge at your location. Add a kerf to the bottom edge of this fence, for the dust, as well. This can just be a block of wood clamped down, or screwed down, to a sub table.
I hope this all helps, & remember it's just woodwork
Oh, and to check your doors & cabinet fronts for square, just measure the diagonals corner to corner of the entire cabinet face or door face. If you place a combo. square in the cab. corners & on the door corners, you may not be satisfied that it looks square enough. That's when you need to step back & look at the big picture, the whole assembly. A melamine or plywood carcass might not look perfect against a small square, but that won't affect how the doors align & adjust on the assembled whole. I build some wall units with 20 to 35, or more, doors & drawer fronts, spread across a large wall in a big room or business. The doors, on euro hinges, will have 3/32" spaces when done & when you look at the finished assembly all will align perfectly, after the final hinge adjustments. If any thing is not perfect at this point, the spaces will show as tapers, & at 3/32" it shows. By focusing on the whole at this point the assembly is easy. By focusing on the individual hardwares, as they are installed, (& your joinery), you'll assure a perfect assembly at the end, each time.
P.S. as far as the fancy jigs & devices in the catalog go. Most are not essential to a professional, at least not all the fancy catalog versions. We've experienced an explosion in interest & the catalogs make alot of money, not furniture. I make furniture & not much money, ha-ha. I see an awful lot of the jigs I've been using for years in the shop, made from scrapwoods of the floor, now in the catalogs. They are not my jigs either, they are common to professionals. Things like beams for a router to cut radii, & elipse jigs. Router tables themselves are made from plywoods & clamped to horses. In my shop I refine my jigs & keep them on the wall. I never considered a value for these items, yet they produce alot of my work, repeatedly & consistently, some for years. Some of the catalog jigs are based on good solid proven designs & others are bells & whistles. Keep it simple.
