Finishing up the F-706 Bulkhead - 6 hours

I took a couple days off from the build and took the kids skiing in the evenings as the weather has been quite nice. I also took a bit of time to read ahead in some of the build logs to get a better understanding of how all the pieces go together and some of the potential gotchas.

One of the things that I was dreading was drilling the wiring holes on the F-705A crossbar. There is not much room to fit these holes and maintain proper edge distance. Also opening up holes with the uni-bit isn't always as precise as I want it to be as the piece can wander if you are not really careful. First thing I like to do is mark-out my hole locations and also mark out the edge distance limits. I ended up deciding to modify Van's dimension slightly so the wiring holes are centered between the rivet holes. The small hash marks are minimum acceptable edge distance locations.

I set up the drill press and clamped a piece of oak as a guide. Slowly I opened up the holes.
  
Don't let the pictures fool you....this was a very slow and methodical process.

The holes are opened up and I am better than minimum edge distance on all 4 rivet holes. The worst offender seems to be the upper right and that one measures 0.2655" center to edge so we are in great shape.

I then opened up the 5/8" holes for the rudder cables.

Next I worked at trimming the two seatbelt anchors to clear the ribs. The pilot left side, and co-pilot right side need trimming. Again, this was a very slow and painful process for me as I took my time, measured, cut, fit, trim again, fit, trim again. Vans indicates minimum edge distance here is 2 x bolt diameter from the center of the hole to the edge. We have tons of room on the pilot side, however co-pilot side is a bit closer (but still within) edge limits. This is because Vans has you drill all four of the left side anchors to the dimension on the plans. I think a better way is to drill the left side anchors on the pilot side, and the right side anchors on the co-pilot side to the dimensions on the drawings first. Then backdrill the adjacent anchor. This would allow a perfect mirror, and the result is that both anchors have tons of edge distance room.

Next order of business is to drill the flap blocks. Took me some time to find where these were as I did not open the electric flap motor bag. I figured out that they are in that bag from reading Mike Bullocks build log. I inventoried all of the hardware and then set up for the drilling. (Funny, my blocks are different thicknesses, so I had to be careful when marking out my dimensions) The right block is clearly thicker.

Drilling in plastic like this is a bit tricky as the piece always wants to grab on to the drill bit. So I was sure to clamp everything down!

Next, since I didnt want to start in on a whole new piece this late in the evening. I opted to just tap the threads in the rear tie-down bar.