Hello again and thanks for he replies.

Dan, the reamers I've been using are "step" reamers sold by the hobby shops to ream the prop center hole. There has always been a "step" that fits existing hole. Is this not the same purpose as the pilot on the counter bore you referenced?

Speed, nice to hear from you, and your advise does seem like the simplest method and which is probably what I'll do. K & S does show some 5mm brass tube with .45mm wall, . . . I may attempt to make a bushing for the drill jig I have as I to am concerned of the drill wandering.

Again, Many Thanks
Mike Brennan
t-man49 in Al