Quote Originally Posted by mrgeoff View Post
They had to have a form in the part to turn it with.
Slot is fairly cheap. Flats would be 2 cutters, or 2 operations minimum.

As the centres are quite close, a multi spindle tool would have struggled, and this is before the days of CNC.
How was this 1925 made? In examining it there appears to be no end cap at all. Was it milled from solid steel? Was it cheaper to ream it clear through and end cap it?