How many screws do you need?

DC-3 Wing Attachment Flange and Bolts

Iaman has been perusing the Hollywood archives again:

Watching a good old John Wayne movie, with Marshall Dillon (James Arness) as a fellow pilot flying a C-47 [DC3] 

I wonder alot about airplane wing spars.  Wondering about the main DC3 wing spar, I didn't find wing spars. Each wing was attached with ~365 1/4' bolts on a flange. 

Neat DC-3 site.