The Hill & Adams patent was the first design of this
type of a tool in the United States. It was
manufactured, presumably, by the patentees and
sold across the country by major tool
The title of the patent doesn't reflect clearly the
purpose of this new contraption. However, in the
narrative, the authors used term "diagonal
bit-holder" to describe the mechanics of the joint
that makes it possible to transfer rotation between
two shafts connected in an angle and this is how the
device was named in later publications.
The initial paragraphs of the patent narrative state
the objectives that guided the development of the
"This bit-holder is intended to be used for boring
holes near to the walls of a room or in a corner,
and in many places where holes cannot be made by the
straight bit or auger when used in the common
bit-stock. Letters Patents of the United States have
been granted for diagonal bit-holders in which a
universal joint or beveled gears are used, and our
improvement does not relate to these parts of the
instrument, but consists mainly in the mode of
making the two bearings and connecting them with
each other by means of the globular casing which
encloses the beveled gears."
The text also refers to the patent No.
18,282 previously awarded to Benjamin B.
Hill in which he addressed the use of “universal
joint or beveled gears” in order to create diagonal
This is the photograph of the device. It was found
on the WorthPoint website.