rfw1953,
Are you using the Great Planes hinge slotting tool for your large Du-Bro hinges? They have come out with some blades that are for thick nylon hinges (I think they may have three different thicknesses, but I'm not sure). I don't know if these blades are the correct thickness for the hinges you are using, but it sure would be alot easier than the old knife blade method! It's kind of a pain to keep changing the blades back and forth for each project. If you do enough hinging, it might be worth buying a couple slotters to avoid the hassel.

I used the nylon pinned hinges on a smaller plane, and secured them with epoxy (after roughing up the surfaces). They are holding well after four years. On a high stress plane, it might be worth using epoxy then pinning through the bottom of the surface with some tooth picks. I read a good tip to cover the tooth pick holes by punching out a little circle of Monokote with a paper hole puncher, then iron on w/ a trim tool.

I think I will also use the Du-Bro 1/4 scale pinned hinges on my Pitts.

Pilgrim