RE: Dubro Hinges
It's a demo so you can see what he is doing. How old is this vid?? Pacer quit making hinge glue a couple years ago. The hinge slotting tools he is using are old school, I haven't used mine in years. They really removed too much wood, then the slot machine came out. I still use my exacto knife and a knife with a couple of exacto saw blades in the handle to cut some slots. The slot machine really made things easier!!
The OP was asking about Hinge Pins and not flat hinges anyway. There is a jig/guide you can buy so the holes you drill are centered, it comes with two sizes of guides for large and medium hinges. Hinge pins work well of some models and not so well on others. ARFs I would not use pins in, you don't know how much wood on the LE and TE there is.
When I build a plane I make sure I glue in added wood in the area I plane on hinging with both flat and pin hinges so I have some added area to glue to. Without the Pacer glue I use Gorilla glue or epoxy. I do open up the area of the hinge center on both the LE and TE so they leave very little hinge gap, I use both a square cut and a bevel.
There isn't a lot to say about installing hinges but I have seen pages written about them?