Safely Installed. Leitz Summicron 50mm DR

There is something very unnerving about drilling holes into a freshly-varnished panel...  Are the holes in exactly the right spot, did I measure accurately - twice or thrice -?  It took almost an hour to measure everything, drill holes and install.  But the important part; no errors.
I had a chuckle: the handles are held in place by long threaded screws which fasten with tiny nuts on the inside of the panel.  The nut size required a 6mm combination wrench to tighten.  I have such a tool, bought in 1978, never used until today!  The story can be found here.