Saturday Jan 8, 2011 (5 hours)
We finished locating and match drilling the spars
We had not attached the T06-06 Clip to the T06-03 Forward Spar Fitting. To locate those horizontally the plans show a dimension from the center of a mounting hole on the Forward Spar Fitting, a tricky measurement to make. We used a centerline mark on the Forward Spar Fitting out to the rib . Vertically we used a centerline and checked with the Leading Edge Rib.
Took me a little while to catch up to how Dan was locating the Leading Edge Ribs (T04-06) to the Forward Spar Assembly (T03-05). We cut a .125 thick piece of aluminum as the spacer to locate the rib away from the spar. Dan had previously marked the vertical centerline of the rib and the centerline of the spar. To align these marks we used a shim between the bottom of the rib and the table (turns out the thickness os a ruler and a piece of .032 was perfect). With the rib aligned we matched drilled it in place.
Dan used his paper templates to locate the tip ribs on the frame. The frame is complete!
Once we had the frame match drilled and cleco-ed together we decided to up drill to a #30 right away (just the frame assembly holes, not the skin holes). Sure was nice having one person pull clecos while the other kept drilling. We used a 6″ #30 drill bit in a couple spots, like on the tip ribs which were close to the bench top.
We cut a section of .025 for the rudder skin off a 4’x8′ sheet. The cut was full width (4′) and we scored it. We line up the score cut with the end of the table, place a 4′ straight edge underneath, clamp it down and push down on the other side of the score with a piece of 4′ steel angle. The two us were pushing pretty hard to get the sheet to break (we even flexed the scoring by rotating the sheet up and down). We need to find a better method, especially when we need a piece of .032, so we might try a router next. A variable speed at its slowest rpm might be the trick.