The associated pdf file is a sketch of the
handle parts of an Ellis dividing head.  A
few dimensions are left to the builder.  
The dimensions have not been checked; that
is left to the builder, too.  The plunger
tip would benefit from hardening.  Additionally,
the plunger should fit closely in the handle 
bore, and the plunger tip should be concentric
with the body to minimize indexing errors.