The outside diameter of the frame end, the tenon, is 20/32 inch but the inside diameter of the ferrule is 24/32 inch.  In addition, the casting of this tenon does not have a sharp, 90 degrees angle to the edge of the frame and existing slope prevents a ferrule to fit snugly. 

Consequently, the ferrule is a free-floating part that does not serve its purpose.  I believe these parts should fit tight to each other and do not leave any wiggle room.  However, it is not the case on drills I have examined.  This creates overall pressures distribution problem during the drill use.

Here is a cut-out of the assembly.   As you can see, the work of controlling the drill is performed only by the wooden handle attached to the threaded rod, without any support from the ferrule or surfaces of the tenon and wood of the handle touching together.  In correct design and execution these gaps would be eliminated and provide for much better distribution of pressure on wooden handle.

The model released in 1903 does not have these problems.  When the handle is installed it does not have any gaps in the spaces described previously.

First, the tenon is machined to precise diameter.  The handle ferrule will fit tightly on this tenon and surface of the wood will touch the surface of the tenon.  This is a winning combination.  I have never seen 1903 release with cracked handle.

The shape to remember...  It is slim and nice design.  It will change in a few years to accommodate different approach to the handle rod - it will be separate machined screw, installed in larger housing with an inside thread.