6/26/2005
This morning I started on the wing. The first step was to countersink the holes in the main spar that plate nuts are attached to for attaching the fuel tank. There are #19 holes for the screws and #40 for the rivets that hold the plate nuts. Countersinking the #40 holes was a snap as it was easy to use a rivet to make sure the depth was right. The #19 holes were a different matter.
Vans says to use a countersink with a #30 pilot for countersinking the #19 holes. I had read on other web sites that this is a bad idea so I decided to try this first on a scrap piece. As expected, it wobbled around in the hole and made a mess of it. I made a guide with a #30 hole out of some scrap angle. The plate nut holes don't seem to be evenly spaced apart so it wasn't possible to attach them with clecos. I had to use clamps instead which meant I had to eyeball the guide hole. This worked out well but was tedious.
The tape in the pictures was to keep the metal shavings from getting stuck between the pieces of the spar.
I finished the #30 plate nut holes on both spars and finished the #19 ones on one of the spars. Lots of holes. I don't know if I have said this yet - the spar is absolutely beautiful. I hope I don't screw it up.
