Brief Description: Marking holes for 405 forward flange
Today was one of those slow days. I have read a few builder sites and the drilling of the upper hole in the forward flange of the 405 rib can cause edge distance issues with the 810 reinforcing angle. I did not want to just mark the holes based on the DWG Sec D-D, other builders have recommended amending these figures to help prevent the edge distance issue. I decided to clamp the parts together, what I came up with after using calipers to measure each side to see how the hole would land was to cut a gap in a paint stick. I then slid this over all of the parts (see photos below). This allowed me to get a good feel for where the center of the hole would end up on the 810 angle. I will include a photo after the hole is drilled to see how close I came.
I measured and drew lines for minimum edge distance then I tried to lay out the holes so that the edge distance had some wiggle room. One thing I did that I did not need to do was drill the lower holes centered on the mark for minimum edge distance. This hole could have been set a little above the minimum since the 814 angle that this hole goes into is much thicker so edge distance would not be a problem. I was so focused on getting the upper hole right at the edge distance to minimize issues with the 810 angle, I marked and drilled the hole for the lower 405 the same. I just have no room for error when this hole gets final drilled to size, the holes are under sized now and will get match drilled in another step.
