Final Up-Drilling of Wing Attach Assemblies

[Bryan Cotton]

Kevin,
Welcome back! For me the .3725 reamer was right. Mic up your bolts, and even better drill and ream some scrap to check the fit on your bolts. The .3725 worked for me on the hummelbird wings and years later was good on the Waiex wings.

For bushings I bought some 3/8" OD 1/4" ID 4130 from Spruce. They are a bit tight to slip into the holes. I will call in a favor from a friend with a lathe and turn them down a bit. I am a ways away from rigging but my thought was to drill the forward holes to 1/4", pop the wings off, drill and ream the forward angle up to size, then put the wings back on using the long bushings as the wing pin. Then with the 1/4" hole accurately located I could pop the rear angles off and drill/ream them to size. Alternatively, you can use your nicely drilled spar holes as a drill guide. You could always clamp a drill block on the back side to protect the spar blocks. By drill block I mean a piece of aluminum or steel with a .3725 hole in it.

[kevinh]

Thanks Bryan, that helps a lot.