Van's RV-9A in Aurora

The Big Picture

The Big Picture
Flying! 8/28/2011

Wednesday, January 16, 2008

Last night finished the countersinking on the HS spars and doublers. It took .9 hours, but the actual machine work was only about 3 tenths. As I was getting setup, I discovered that the #30 countersink bit in the Avery cage/bit collection is about 1/128" too big for a #30 hole. It simply wouldn't fit any of the #30 holes I had drilled. At first I started thinking that I had only drilled the holes to 1/8". But the #30 drills I have all fit, and and the AD4 rivets fit. Using a caliper I confirmed that the pilot on the countersink bit is 8.5 64th's where the #30s are just a shade over 8 64ths (.129 according the Standard Aircraft text). I guess I'll have to email Avery and see what they say about it. After about 40 minutes of trying to figure out what was wrong, I decided I hadn't screwed anything up, the countersink bit was wrong, and to just use the #40 bit to do the machining. It chattered a bit, but slow feeding reduced that problem. 20 minutes later, 12 nice countersunk holes.

Now all HS preassembly is done. Next up priming. The weather might not cooperate, so I will start on the vertical stabilizer until the weekend.

Also got in some back riveting practice, using the plate Granger made. The rivets turned out great, and now I feel confident that I can backrivet without messing up any thing. More practice needed with the bucking bar, though. Turning the pressure down to 50 really does help.