24/02/2008 - The work begins with the spars

The day started with setting up the countersink cages for the work on the plate nuts which will attach the fuel tank skins to the spar with #8 screws.  The correct diameter is somewhere between 0.365 & 0.375; so like most others I plumped for the middle.  A quick check with a #8 dimpled 0.32 Aluminium skin test piece showed the countersink to be the correct size.

The plans state cutting off a head screw to check; so I did that as well.

Like many other builders I did not use the plate nut to centre the countersink bit; but plumped for creating my won jig.  I cur a piece of aluminium that I used for getting the rudder trailing edge straight a few months back.  A made a few pilot holes using #30 drill.

Time for the first step.  Well ok the picture is rubbish; but that's cause I was shaking with nerves !!! its a big deal taking the drill to these lovely spars; especially as they cost a lot!!

Anyway I was happy with the result; so I needed to push on.  There are 30 on each side with 4 sides in total.  That made ...ur .... 120 countersinks to be done !!

4 hours later ! and there all done.  Don't know what all the fuss was about at the start ;-)