The upper frames 1, 1a thru 4 are shown fitted up to the longerons and to the project supplied lower fuse frames.
The photos demonstrate the process of marking out one hole for a "pass through" in the fuselage cockpit side.
There are many brackets and doublers fitted to these frames, both upper and lower.
A surprising amount of work for a few holes! This process is repeated time again as required till all brackets are fitted and frames are complete as per the Curtiss drawings and original sample structures.