Started Countersinking Cabin Frame

I disassembled and deburred all of the channel holes in the cabin frame.  I then started working on countersinking all of the necessary holes.  These are the ones in the channels that are used to rivet on the splice plates.



I also did all of the outer holes along the forward channels.  These are a little trickier since the curve prevents using the countersink cage to set the depth.  Basically, these all need to be done freehand which makes these holes fairly time consuming.