The thread Chris posted reminded me of a piercing saw that I have. It was made by a friend's grandfather while he was learning tool and die making on the G.I. Bill after WWII.
The saw is made up of 14 pieces, only on 5 of them factory made. These 5 are the 4 socket head cap screws and the cast ali handle. Currently one of the collets that holds the blade is broken and I haven't taken the time to make a new one. From the appearance of the break it was due to the heat treatment leaving it brittle.
Should anyone want to duplicate this saw I can furnish dimensions and improved photos.
Here is the saw.

The 14 parts. This view shows the slots that allow the two top rails to be clamped tightly.

Another view of the parts.

Here is the broken collet that must be replaced.

Joe