We are getting ready to head to Airventure for a couple of days this week so today's goal was to get all the miscellaneous tank prep work done so that when we come back, we could start sealing this darn thing up.  I will be so glad when I have the fuel tanks behind me.

This morning, I started by match drilling all the holes.  Using the sharpie marker to track which holes have been drilled has worked so well for my absent mind, I continued to use it when drilling the fuel tank.  You quickly forget how many holes are in this tank until you have to drill and debur them.

In the picture below, I placed a 2 x 4 scrap behind the screw attach holes and then drilled them out to size #19.  The 2 x 4 worked well to hold the skin and prevent it from chattering.

Next, I clecoed the stiffeners to the tank and labeled them with the same labeling convention I used on the right wing.  'A' = forwards, 'B' = aft and 1-6 from inboard to outboard.  Then I match drilled all the stiffeners.

Are you starting to see a recurring theme with this prep work????

On to the fuel drain.  When I had it positioned where I wanted it, I used a set of vise clamps to hold it in place.  I lined up the drain flange so that the forward and aft rivet holes were equally spaced from the edge of the skin.  It doesn't really matter, I just like a little symetry and this is how I lined up the right tank drain.

Looks pretty good from this picture.

Next it was onto the fuel cap.  Since these are locking caps, the flange has a definite orientation (one because the filler neck is curved to line up with the skin and TWO, the locking cap has to be oriented in a specific location so the filler cap sits in the flange correctly.  See my right fuel tank log entries for more detail). 

Drilliing this flange kind of made me nervous as these fuel filler caps are not all that cheap.  $90 a piece.  All I need to do is misdrill this filler flange to p_ss me off.  Everything has gone great since starting this right wing.  I didn't want to make my first mistake on the wing here.

Can't forget to machine countersink the filler neck flange.  I used my test coupon with the tank dimple die to set the countersink to the proper depth.

Then it was onto countersinking the tank skin where it is riveted to the rear baffle.  Just cleco the rear baffle in place to give the countersink pilot a guide point.

I countersunk the rivet holes a couple of thousandths of a inch here to allow for tank sealant between the tank skin and the factory rivet head.

Just a staged photograph what I worked on today.  I got so busy, I forgot to take pictures as I went along.  It is kind of boring anyway....  You know the routine: drill, debur, dimple, repeat....

Things yet to do before sealing:

1. Debur outside of skin
2. Dimple ribs
3. Dimple Skin
4. Dimple stiffeners
5. Drill ribs for capacitance senders
6. Fabricate vent clip (make 2 in case I screw up the first one while riveting)