Modifying the forming block^1h

A small session of modifying the forming block.

Since three flange flaps (each side) need to be offset towards the center of the fuselage, I machined the indents in the block for them. The top ones need to be indented by the thickness of the longeron (0.125"). The middle ones need to provide the space for the J-channel (0.025"). The bottom one should be offset for the J-channel and the thick bottom skin (0.025" + 0.032").

To modify, I marked the location of these flaps, put the block in the milling machine, and used a regular endmill to machine 5/8" wide slots.

The machined indents.

The final result.